diff --git a/.github/stale.yml b/.github/stale.yml
deleted file mode 100644
index 9eb6c2c8..00000000
--- a/.github/stale.yml
+++ /dev/null
@@ -1,12 +0,0 @@
-daysUntilStale: 60
-daysUntilClose: 7
-exemptLabels:
-  - pinned
-  - security
-staleLabel: stale
-markComment: >
-  This issue has been automatically marked as stale because it has not had
-  recent activity. It will be closed if no further activity occurs. Thank you
-  for your contributions.
-closeComment: false
-only: issues
diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
new file mode 100644
index 00000000..8e13fd73
--- /dev/null
+++ b/.pre-commit-config.yaml
@@ -0,0 +1,20 @@
+# See https://pre-commit.com for more information
+# See https://pre-commit.com/hooks.html for more hooks
+repos:
+  - repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: v4.0.1
+    hooks:
+      - id: check-merge-conflict
+      - id: check-json
+      - id: debug-statements
+      - id: mixed-line-ending
+        args: [--fix=lf]
+  - repo: https://github.com/asottile/pyupgrade
+    rev: v2.29.1
+    hooks:
+      - id: pyupgrade
+        args: [--py36-plus]
+  - repo: meta
+    hooks:
+      - id: check-hooks-apply
+      - id: check-useless-excludes
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4dd4f866..e2182cc5 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,10 +10,12 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 ### Added
 - Add fields that populate on create but not update `SOCIAL_AUTH_IMMUTABLE_USER_FIELDS`
 - Add Gitea oauth2 backend
+- Add Twitch OpenId backend
 
 ### Changed
 - Fixed Slack user identity API call with Bearer headers
 - Fixed microsoft-graph login error
+- Fixed Twitch OAuth2 backend
 
 
 ## [4.1.0](https://github.com/python-social-auth/social-core/releases/tag/4.1.0) - 2021-03-01
diff --git a/setup.py b/setup.py
index e94f7674..897f4214 100644
--- a/setup.py
+++ b/setup.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 import re
 
 from os.path import join, dirname
@@ -21,7 +20,7 @@
 def long_description():
     try:
         return open(join(dirname(__file__), 'README.md')).read()
-    except IOError:
+    except OSError:
         return None
 
 
@@ -33,12 +32,12 @@ def read_version():
 
 
 def read_requirements(filename):
-    with open(filename, 'r') as file:
+    with open(filename) as file:
         return [line for line in file.readlines() if not line.startswith('-')]
 
 
 def read_tests_requirements(filename):
-    return read_requirements('social_core/tests/{0}'.format(filename))
+    return read_requirements(f'social_core/tests/{filename}')
 
 
 requirements = read_requirements('requirements-base.txt')
diff --git a/social_core/actions.py b/social_core/actions.py
index eee563d8..81427156 100644
--- a/social_core/actions.py
+++ b/social_core/actions.py
@@ -92,7 +92,7 @@ def do_complete(backend, login, user=None, redirect_name='next',
     if redirect_value and redirect_value != url:
         redirect_value = quote(redirect_value)
         url += ('&' if '?' in url else '?') + \
-            '{0}={1}'.format(redirect_name, redirect_value)
+            f'{redirect_name}={redirect_value}'
 
     if backend.setting('SANITIZE_REDIRECTS', True):
         allowed_hosts = backend.setting('ALLOWED_REDIRECT_HOSTS', []) + \
diff --git a/social_core/backends/apple.py b/social_core/backends/apple.py
index edfab315..42d707ec 100644
--- a/social_core/backends/apple.py
+++ b/social_core/backends/apple.py
@@ -128,8 +128,8 @@ def decode_id_token(self, id_token):
                 audience=self.get_audience(),
                 algorithms=['RS256'],
             )
-        except PyJWTError:
-            raise AuthFailed(self, 'Token validation failed')
+        except PyJWTError as error:
+            raise AuthFailed(self, f'Token validation failed by {error}')
 
         return decoded
 
diff --git a/social_core/backends/asana.py b/social_core/backends/asana.py
index d19fd140..7e050378 100644
--- a/social_core/backends/asana.py
+++ b/social_core/backends/asana.py
@@ -28,7 +28,7 @@ def get_user_details(self, response):
 
     def user_data(self, access_token, *args, **kwargs):
         return self.get_json(self.USER_DATA_URL, headers={
-            'Authorization': 'Bearer {}'.format(access_token)
+            'Authorization': f'Bearer {access_token}'
         })
 
     def extra_data(self, user, uid, response, details=None, *args, **kwargs):
diff --git a/social_core/backends/atlassian.py b/social_core/backends/atlassian.py
index f76969f9..cb8e09a7 100644
--- a/social_core/backends/atlassian.py
+++ b/social_core/backends/atlassian.py
@@ -30,8 +30,8 @@ def get_user_details(self, response):
 
     def user_data(self, access_token, *args, **kwargs):
         resources = self.get_json('https://api.atlassian.com/oauth/token/accessible-resources',
-                                  headers={'Authorization': 'Bearer {}'.format(access_token)})
+                                  headers={'Authorization': f'Bearer {access_token}'})
         user_info = self.get_json('https://api.atlassian.com/ex/jira/{}/rest/api/2/myself'.format(resources[0]['id']),
-                                  headers={'Authorization': 'Bearer {}'.format(access_token)})
+                                  headers={'Authorization': f'Bearer {access_token}'})
         user_info['resources'] = resources
         return user_info
diff --git a/social_core/backends/azuread.py b/social_core/backends/azuread.py
index 3ca9908e..2e37af51 100644
--- a/social_core/backends/azuread.py
+++ b/social_core/backends/azuread.py
@@ -45,7 +45,7 @@ class AzureADOAuth2(BaseOAuth2):
     ACCESS_TOKEN_URL = 'https://login.microsoftonline.com/common/oauth2/token'
     ACCESS_TOKEN_METHOD = 'POST'
     REDIRECT_STATE = False
-    DEFAULT_SCOPE = ['openid', 'profile', 'user_impersonation']
+    DEFAULT_SCOPE = ['openid', 'profile', 'user_impersonation', 'email']
     EXTRA_DATA = [
         ('access_token', 'access_token'),
         ('id_token', 'id_token'),
@@ -70,7 +70,7 @@ def get_user_details(self, response):
             response.get('family_name', '')
         )
         return {'username': fullname,
-                'email': response.get('upn'),
+                'email': response.get('email', response.get('upn')),
                 'fullname': fullname,
                 'first_name': first_name,
                 'last_name': last_name}
diff --git a/social_core/backends/azuread_b2c.py b/social_core/backends/azuread_b2c.py
index 7662f41e..a9f3842c 100644
--- a/social_core/backends/azuread_b2c.py
+++ b/social_core/backends/azuread_b2c.py
@@ -165,7 +165,7 @@ def get_public_key(self, kid):
         for key in resp.json()['keys']:
             if key['kid'] == kid:
                 return self.jwt_key_to_pem(key)
-        raise DecodeError('Cannot find kid={}'.format(kid))
+        raise DecodeError(f'Cannot find kid={kid}')
 
     def user_data(self, access_token, *args, **kwargs):
         response = kwargs.get('response')
diff --git a/social_core/backends/azuread_tenant.py b/social_core/backends/azuread_tenant.py
index 53b6501c..c17f8bc1 100644
--- a/social_core/backends/azuread_tenant.py
+++ b/social_core/backends/azuread_tenant.py
@@ -79,7 +79,7 @@ def get_certificate(self, kid):
                 x5c = key['x5c'][0]
                 break
         else:
-            raise DecodeError('Cannot find kid={}'.format(kid))
+            raise DecodeError(f'Cannot find kid={kid}')
 
         return load_der_x509_certificate(base64.b64decode(x5c),
                                          default_backend())
diff --git a/social_core/backends/beats.py b/social_core/backends/beats.py
index 4dda471a..61de4038 100644
--- a/social_core/backends/beats.py
+++ b/social_core/backends/beats.py
@@ -23,8 +23,8 @@ def get_user_id(self, details, response):
 
     def auth_headers(self):
         return {
-            'Authorization': 'Basic {0}'.format(base64.urlsafe_b64encode(
-                ('{0}:{1}'.format(*self.get_key_and_secret()).encode())
+            'Authorization': 'Basic {}'.format(base64.urlsafe_b64encode(
+                '{}:{}'.format(*self.get_key_and_secret()).encode()
             ))
         }
 
@@ -61,5 +61,5 @@ def user_data(self, access_token, *args, **kwargs):
         """Loads user data from service"""
         return self.get_json(
             'https://partner.api.beatsmusic.com/v1/api/me',
-            headers={'Authorization': 'Bearer {0}'.format(access_token)}
+            headers={'Authorization': f'Bearer {access_token}'}
         )
diff --git a/social_core/backends/chatwork.py b/social_core/backends/chatwork.py
index b69a627e..82d71f05 100644
--- a/social_core/backends/chatwork.py
+++ b/social_core/backends/chatwork.py
@@ -23,12 +23,12 @@ class ChatworkOAuth2(BaseOAuth2):
 
     def api_url(self, path):
         api_url = self.setting('API_URL') or self.API_URL
-        return '{0}{1}'.format(api_url.rstrip('/'), path)
+        return '{}{}'.format(api_url.rstrip('/'), path)
 
     def auth_headers(self):
         return {
             'Authorization': b'Basic ' + base64.b64encode(
-                '{0}:{1}'.format(*self.get_key_and_secret()).encode()
+                '{}:{}'.format(*self.get_key_and_secret()).encode()
             )
         }
 
diff --git a/social_core/backends/coding.py b/social_core/backends/coding.py
index 81f998b1..5bbf138c 100644
--- a/social_core/backends/coding.py
+++ b/social_core/backends/coding.py
@@ -43,6 +43,6 @@ def user_data(self, access_token, *args, **kwargs):
     def _user_data(self, access_token, path=None):
         url = urljoin(
             self.api_url(),
-            'account/current_user{0}'.format(path or '')
+            'account/current_user{}'.format(path or '')
         )
         return self.get_json(url, params={'access_token': access_token})
diff --git a/social_core/backends/cognito.py b/social_core/backends/cognito.py
index dabe718b..df6f33af 100644
--- a/social_core/backends/cognito.py
+++ b/social_core/backends/cognito.py
@@ -12,13 +12,13 @@ def user_pool_domain(self):
         return self.setting('POOL_DOMAIN')
 
     def authorization_url(self):
-        return '{}/login'.format(self.user_pool_domain())
+        return f'{self.user_pool_domain()}/login'
 
     def access_token_url(self):
-        return '{}/oauth2/token'.format(self.user_pool_domain())
+        return f'{self.user_pool_domain()}/oauth2/token'
 
     def user_data_url(self):
-        return '{}/oauth2/userInfo'.format(self.user_pool_domain())
+        return f'{self.user_pool_domain()}/oauth2/userInfo'
 
     def get_user_details(self, response):
         """Return user details from their cognito pool account"""
@@ -38,7 +38,7 @@ def user_data(self, access_token, *args, **kwargs):
         """Grab user profile information from cognito."""
         response = self.get_json(
             url=self.user_data_url(),
-            headers={'Authorization': 'Bearer {}'.format(access_token)},
+            headers={'Authorization': f'Bearer {access_token}'},
         )
 
         user_data = {
diff --git a/social_core/backends/coursera.py b/social_core/backends/coursera.py
index ff5f287a..56162bf6 100644
--- a/social_core/backends/coursera.py
+++ b/social_core/backends/coursera.py
@@ -40,4 +40,4 @@ def user_data(self, access_token, *args, **kwargs):
         )
 
     def get_auth_header(self, access_token):
-        return {'Authorization': 'Bearer {0}'.format(access_token)}
+        return {'Authorization': f'Bearer {access_token}'}
diff --git a/social_core/backends/discord.py b/social_core/backends/discord.py
index 24cd847f..25d09127 100644
--- a/social_core/backends/discord.py
+++ b/social_core/backends/discord.py
@@ -1,31 +1,31 @@
-"""
-Discord Auth OAuth2 backend, docs at:
-    https://discord.com/developers/docs/topics/oauth2
-"""
-from .oauth import BaseOAuth2
-
-
-class DiscordOAuth2(BaseOAuth2):
-    name = 'discord'
-    HOSTNAME = 'discord.com'
-    AUTHORIZATION_URL = 'https://%s/api/oauth2/authorize' % HOSTNAME
-    ACCESS_TOKEN_URL = 'https://%s/api/oauth2/token' % HOSTNAME
-    ACCESS_TOKEN_METHOD = 'POST'
-    REVOKE_TOKEN_URL = 'https://%s/api/oauth2/token/revoke' % HOSTNAME
-    REVOKE_TOKEN_METHOD = 'GET'
-    DEFAULT_SCOPE = ['identify']
-    SCOPE_SEPARATOR = '+'
-    REDIRECT_STATE = False
-    EXTRA_DATA = [
-        ('expires_in', 'expires'),
-        ('refresh_token', 'refresh_token')
-    ]
-
-    def get_user_details(self, response):
-        return {'username': response.get('username'),
-                'email': response.get('email') or ''}
-
-    def user_data(self, access_token, *args, **kwargs):
-        url = 'https://%s/api/users/@me' % self.HOSTNAME
-        auth_header = {'Authorization': 'Bearer %s' % access_token}
-        return self.get_json(url, headers=auth_header)
+"""
+Discord Auth OAuth2 backend, docs at:
+    https://discord.com/developers/docs/topics/oauth2
+"""
+from .oauth import BaseOAuth2
+
+
+class DiscordOAuth2(BaseOAuth2):
+    name = 'discord'
+    HOSTNAME = 'discord.com'
+    AUTHORIZATION_URL = 'https://%s/api/oauth2/authorize' % HOSTNAME
+    ACCESS_TOKEN_URL = 'https://%s/api/oauth2/token' % HOSTNAME
+    ACCESS_TOKEN_METHOD = 'POST'
+    REVOKE_TOKEN_URL = 'https://%s/api/oauth2/token/revoke' % HOSTNAME
+    REVOKE_TOKEN_METHOD = 'GET'
+    DEFAULT_SCOPE = ['identify']
+    SCOPE_SEPARATOR = '+'
+    REDIRECT_STATE = False
+    EXTRA_DATA = [
+        ('expires_in', 'expires'),
+        ('refresh_token', 'refresh_token')
+    ]
+
+    def get_user_details(self, response):
+        return {'username': response.get('username'),
+                'email': response.get('email') or ''}
+
+    def user_data(self, access_token, *args, **kwargs):
+        url = 'https://%s/api/users/@me' % self.HOSTNAME
+        auth_header = {'Authorization': 'Bearer %s' % access_token}
+        return self.get_json(url, headers=auth_header)
diff --git a/social_core/backends/discourse.py b/social_core/backends/discourse.py
index 4c8bdc4f..905392b1 100644
--- a/social_core/backends/discourse.py
+++ b/social_core/backends/discourse.py
@@ -39,7 +39,7 @@ def auth_url(self):
             'sso': base_64_payload,
             'sig': payload_signature
         })
-        return '{0}?{1}'.format(self.get_idp_url(), encoded_params)
+        return f'{self.get_idp_url()}?{encoded_params}'
 
     def get_idp_url(self):
         return self.setting('SERVER_URL') + '/session/sso_provider'
diff --git a/social_core/backends/douban.py b/social_core/backends/douban.py
index ff931c0a..96a07102 100644
--- a/social_core/backends/douban.py
+++ b/social_core/backends/douban.py
@@ -55,5 +55,5 @@ def user_data(self, access_token, *args, **kwargs):
         """Return user data provided"""
         return self.get_json(
             'https://api.douban.com/v2/user/~me',
-            headers={'Authorization': 'Bearer {0}'.format(access_token)}
+            headers={'Authorization': f'Bearer {access_token}'}
         )
diff --git a/social_core/backends/dribbble.py b/social_core/backends/dribbble.py
index 7381e6d4..d8835376 100644
--- a/social_core/backends/dribbble.py
+++ b/social_core/backends/dribbble.py
@@ -58,5 +58,5 @@ def user_data(self, access_token, *args, **kwargs):
         return self.get_json(
             'https://api.dribbble.com/v1/user',
             headers={
-                'Authorization': 'Bearer {0}'.format(access_token)
+                'Authorization': f'Bearer {access_token}'
             })
diff --git a/social_core/backends/dropbox.py b/social_core/backends/dropbox.py
index a22b79b1..7a3addb2 100644
--- a/social_core/backends/dropbox.py
+++ b/social_core/backends/dropbox.py
@@ -26,6 +26,6 @@ def user_data(self, access_token, *args, **kwargs):
         """Loads user data from service"""
         return self.get_json(
             'https://api.dropboxapi.com/2/users/get_current_account',
-            headers={'Authorization': 'Bearer {0}'.format(access_token)},
+            headers={'Authorization': f'Bearer {access_token}'},
             method='POST'
         )
diff --git a/social_core/backends/eveonline.py b/social_core/backends/eveonline.py
index 1b7e5dc1..33b15be3 100644
--- a/social_core/backends/eveonline.py
+++ b/social_core/backends/eveonline.py
@@ -38,5 +38,5 @@ def user_data(self, access_token, *args, **kwargs):
         """Get Character data from EVE server"""
         return self.get_json(
             'https://login.eveonline.com/oauth/verify',
-            headers={'Authorization': 'Bearer {0}'.format(access_token)}
+            headers={'Authorization': f'Bearer {access_token}'}
         )
diff --git a/social_core/backends/exacttarget.py b/social_core/backends/exacttarget.py
index a066cdde..5beeacc7 100644
--- a/social_core/backends/exacttarget.py
+++ b/social_core/backends/exacttarget.py
@@ -45,7 +45,7 @@ def get_user_id(self, details, response):
                 'email': 'example@example.com'
             }
         """
-        return '{0}'.format(details.get('id'))
+        return '{}'.format(details.get('id'))
 
     def uses_redirect(self):
         return False
diff --git a/social_core/backends/facebook.py b/social_core/backends/facebook.py
index 11f70dd1..c8ef724f 100644
--- a/social_core/backends/facebook.py
+++ b/social_core/backends/facebook.py
@@ -14,7 +14,7 @@
                          AuthMissingParameter
 
 
-API_VERSION = 8.0
+API_VERSION = 14.0
 
 
 class FacebookOAuth2(BaseOAuth2):
@@ -65,7 +65,7 @@ def get_user_details(self, response):
 
     def user_data(self, access_token, *args, **kwargs):
         """Loads user data from service"""
-        params = self.setting('PROFILE_EXTRA_PARAMS', {})
+        params = self.setting('PROFILE_EXTRA_PARAMS', {}).copy()
         params['access_token'] = access_token
 
         if self.setting('APPSECRET_PROOF', True):
@@ -213,7 +213,7 @@ def auth_html(self):
     def load_signed_request(self, signed_request):
         def base64_url_decode(data):
             data = data.encode('ascii')
-            data += '='.encode('ascii') * (4 - (len(data) % 4))
+            data += b'=' * (4 - (len(data) % 4))
             return base64.urlsafe_b64decode(data)
 
         key, secret = self.get_key_and_secret()
diff --git a/social_core/backends/fitbit.py b/social_core/backends/fitbit.py
index a2f4cde3..768cc8f1 100644
--- a/social_core/backends/fitbit.py
+++ b/social_core/backends/fitbit.py
@@ -59,9 +59,9 @@ def user_data(self, access_token, *args, **kwargs):
         )['user']
 
     def auth_headers(self):
-        tokens = '{0}:{1}'.format(*self.get_key_and_secret())
+        tokens = '{}:{}'.format(*self.get_key_and_secret())
         tokens = base64.urlsafe_b64encode(tokens.encode())
         tokens = tokens.decode()
         return {
-            'Authorization': 'Basic {0}'.format(tokens)
+            'Authorization': f'Basic {tokens}'
         }
diff --git a/social_core/backends/gae.py b/social_core/backends/gae.py
index a6aa8e3e..1919db01 100644
--- a/social_core/backends/gae.py
+++ b/social_core/backends/gae.py
@@ -1,7 +1,6 @@
 """
 Google App Engine support using User API
 """
-from __future__ import absolute_import
 
 from google.appengine.api import users
 
diff --git a/social_core/backends/gitea.py b/social_core/backends/gitea.py
index 1d19a492..5899f42d 100644
--- a/social_core/backends/gitea.py
+++ b/social_core/backends/gitea.py
@@ -24,7 +24,7 @@ class GiteaOAuth2   (BaseOAuth2):
 
     def api_url(self, path):
         api_url = self.setting('API_URL') or self.API_URL
-        return '{0}{1}'.format(api_url.rstrip('/'), path)
+        return '{}{}'.format(api_url.rstrip('/'), path)
 
     def authorization_url(self):
         return self.api_url('/login/oauth/authorize')
diff --git a/social_core/backends/github.py b/social_core/backends/github.py
index 42a8dac6..e8bd2d9e 100644
--- a/social_core/backends/github.py
+++ b/social_core/backends/github.py
@@ -64,8 +64,8 @@ def user_data(self, access_token, *args, **kwargs):
         return data
 
     def _user_data(self, access_token, path=None):
-        url = urljoin(self.api_url(), 'user{0}'.format(path or ''))
-        return self.get_json(url, headers={'Authorization': 'token {0}'.format(access_token)})
+        url = urljoin(self.api_url(), 'user{}'.format(path or ''))
+        return self.get_json(url, headers={'Authorization': f'token {access_token}'})
 
 
 class GithubMemberOAuth2(GithubOAuth2):
@@ -74,7 +74,7 @@ class GithubMemberOAuth2(GithubOAuth2):
     def user_data(self, access_token, *args, **kwargs):
         """Loads user data from service"""
         user_data = super().user_data(access_token, *args, **kwargs)
-        headers = {'Authorization': 'token {0}'.format(access_token)}
+        headers = {'Authorization': f'token {access_token}'}
         try:
             self.request(self.member_url(user_data), headers=headers)
         except HTTPError as err:
diff --git a/social_core/backends/gitlab.py b/social_core/backends/gitlab.py
index 13f51500..3fc7f07b 100644
--- a/social_core/backends/gitlab.py
+++ b/social_core/backends/gitlab.py
@@ -27,7 +27,7 @@ class GitLabOAuth2(BaseOAuth2):
 
     def api_url(self, path):
         api_url = self.setting('API_URL') or self.API_URL
-        return '{0}{1}'.format(api_url.rstrip('/'), path)
+        return '{}{}'.format(api_url.rstrip('/'), path)
 
     def authorization_url(self):
         return self.api_url('/oauth/authorize')
diff --git a/social_core/backends/globus.py b/social_core/backends/globus.py
index a9368081..818f0fbf 100644
--- a/social_core/backends/globus.py
+++ b/social_core/backends/globus.py
@@ -10,6 +10,7 @@
 class GlobusOpenIdConnect(OpenIdConnectAuth):
     name = 'globus'
     OIDC_ENDPOINT = 'https://auth.globus.org'
+    JWT_ALGORITHMS = ['RS256', 'RS512']
     EXTRA_DATA = [
         ('expires_in', 'expires_in', True),
         ('refresh_token', 'refresh_token', True),
diff --git a/social_core/backends/goclio.py b/social_core/backends/goclio.py
index 4d75c1ca..e682e9da 100644
--- a/social_core/backends/goclio.py
+++ b/social_core/backends/goclio.py
@@ -16,7 +16,7 @@ def get_user_details(self, response):
         email = user.get('email', None)
         first_name, last_name = (user.get('first_name', None),
                                  user.get('last_name', None))
-        fullname = '%s %s' % (first_name, last_name)
+        fullname = f'{first_name} {last_name}'
 
         return {'username': username,
                 'fullname': fullname,
diff --git a/social_core/backends/itembase.py b/social_core/backends/itembase.py
index 7938e932..d8330b40 100644
--- a/social_core/backends/itembase.py
+++ b/social_core/backends/itembase.py
@@ -50,14 +50,14 @@ def get_user_details(self, response):
 
     def user_data(self, access_token, *args, **kwargs):
         return self.get_json(self.USER_DETAILS_URL, headers={
-            'Authorization': 'Bearer {0}'.format(access_token)
+            'Authorization': f'Bearer {access_token}'
         })
 
     def activation_data(self, response):
         # returns activation_data dict with activation_url inside
         # see http://developers.itembase.com/authentication/activation
         return self.get_json(self.ACTIVATION_ENDPOINT, headers={
-            'Authorization': 'Bearer {0}'.format(response['access_token'])
+            'Authorization': 'Bearer {}'.format(response['access_token'])
         })
 
     @handle_http_errors
diff --git a/social_core/backends/jawbone.py b/social_core/backends/jawbone.py
index 9805b5f0..c98d71ef 100644
--- a/social_core/backends/jawbone.py
+++ b/social_core/backends/jawbone.py
@@ -48,7 +48,7 @@ def process_error(self, data):
             if error == 'access_denied':
                 raise AuthCanceled(self)
             else:
-                raise AuthUnknownError(self, 'Jawbone error was {0}'.format(
+                raise AuthUnknownError(self, 'Jawbone error was {}'.format(
                     error
                 ))
         return super().process_error(data)
diff --git a/social_core/backends/justgiving.py b/social_core/backends/justgiving.py
index 57c89a52..66de2b36 100644
--- a/social_core/backends/justgiving.py
+++ b/social_core/backends/justgiving.py
@@ -31,7 +31,7 @@ def user_data(self, access_token, *args, **kwargs):
         """Loads user data from service"""
         key, secret = self.get_key_and_secret()
         return self.get_json(self.USER_DATA_URL, headers={
-            'Authorization': 'Bearer {0}'.format(access_token),
+            'Authorization': f'Bearer {access_token}',
             'Content-Type': 'application/json',
             'x-application-key': secret,
             'x-api-key': key
diff --git a/social_core/backends/kakao.py b/social_core/backends/kakao.py
index ceea26fc..9e015eac 100644
--- a/social_core/backends/kakao.py
+++ b/social_core/backends/kakao.py
@@ -39,7 +39,7 @@ def user_data(self, access_token, *args, **kwargs):
         return self.get_json(
             'https://kapi.kakao.com/v2/user/me',
             headers={
-                'Authorization': 'Bearer {0}'.format(access_token),
+                'Authorization': f'Bearer {access_token}',
                 'Content_Type': 'application/x-www-form-urlencoded;charset=utf-8',
             },
             params={'access_token': access_token}
diff --git a/social_core/backends/line.py b/social_core/backends/line.py
index b1cfcf4b..9cb0a527 100644
--- a/social_core/backends/line.py
+++ b/social_core/backends/line.py
@@ -96,7 +96,7 @@ def user_data(self, access_token, *args, **kwargs):
             response = self.get_json(
                 self.USER_INFO_URL,
                 headers={
-                    'Authorization': 'Bearer {}'.format(access_token)
+                    'Authorization': f'Bearer {access_token}'
                 }
             )
             self.process_error(response)
diff --git a/social_core/backends/livejournal.py b/social_core/backends/livejournal.py
index 3e1df99d..795f8f97 100644
--- a/social_core/backends/livejournal.py
+++ b/social_core/backends/livejournal.py
@@ -23,4 +23,4 @@ def openid_url(self):
         """Returns LiveJournal authentication URL"""
         if not self.data.get('openid_lj_user'):
             raise AuthMissingParameter(self, 'openid_lj_user')
-        return 'http://{0}.livejournal.com'.format(self.data['openid_lj_user'])
+        return 'http://{}.livejournal.com'.format(self.data['openid_lj_user'])
diff --git a/social_core/backends/loginradius.py b/social_core/backends/loginradius.py
index 49bfa55d..bdea3a6e 100644
--- a/social_core/backends/loginradius.py
+++ b/social_core/backends/loginradius.py
@@ -65,5 +65,5 @@ def get_user_id(self, details, response):
         """Return a unique ID for the current user, by default from server
         response. Since LoginRadius handles multiple providers, we need to
         distinguish them to prevent conflicts."""
-        return '{0}-{1}'.format(response.get('Provider'),
+        return '{}-{}'.format(response.get('Provider'),
                                 response.get(self.ID_KEY))
diff --git a/social_core/backends/lyft.py b/social_core/backends/lyft.py
index 8c016b45..9e259b26 100644
--- a/social_core/backends/lyft.py
+++ b/social_core/backends/lyft.py
@@ -37,7 +37,7 @@ def get_user_details(self, response):
     def user_data(self, access_token, *args, **kwargs):
         """Loads user data from service"""
         return self.get_json(self.USER_DATA_URL, headers={
-          'Authorization': 'Bearer {0}'.format(access_token)
+          'Authorization': f'Bearer {access_token}'
         })
 
     def auth_complete_params(self, state=None):
diff --git a/social_core/backends/mapmyfitness.py b/social_core/backends/mapmyfitness.py
index 7c202b9b..7311bdd2 100644
--- a/social_core/backends/mapmyfitness.py
+++ b/social_core/backends/mapmyfitness.py
@@ -43,7 +43,7 @@ def user_data(self, access_token, *args, **kwargs):
         key = self.get_key_and_secret()[0]
         url = 'https://oauth2-api.mapmyapi.com/v7.0/user/self/'
         headers = {
-            'Authorization': 'Bearer {0}'.format(access_token),
+            'Authorization': f'Bearer {access_token}',
             'Api-Key': key
         }
         return self.get_json(url, headers=headers)
diff --git a/social_core/backends/mediawiki.py b/social_core/backends/mediawiki.py
index 16565658..f8a5b1ce 100644
--- a/social_core/backends/mediawiki.py
+++ b/social_core/backends/mediawiki.py
@@ -72,7 +72,7 @@ def oauth_authorization_request(self, token):
         state = self.get_or_create_state()
         base_url = self.setting('MEDIAWIKI_URL')
 
-        return '{0}?{1}'.format(base_url, urlencode({
+        return '{}?{}'.format(base_url, urlencode({
             'title': 'Special:Oauth/authenticate',
             self.OAUTH_TOKEN_PARAMETER_NAME: oauth_token,
             self.REDIRECT_URI_PARAMETER_NAME: self.get_redirect_uri(state)
@@ -123,7 +123,7 @@ def get_user_details(self, response):
             raise AuthException(
                 self,
                 'An error occurred while trying to read json ' +
-                'content: {0}'.format(exception)
+                f'content: {exception}'
             )
 
         issuer = urlparse(identity['iss']).netloc
@@ -132,7 +132,7 @@ def get_user_details(self, response):
         if not issuer == expected_domain:
             raise AuthException(
                 self,
-                'Unexpected issuer {0}, expected {1}'.format(
+                'Unexpected issuer {}, expected {}'.format(
                     issuer,
                     expected_domain
                 )
@@ -143,7 +143,7 @@ def get_user_details(self, response):
         if not now >= (issued_at - self.LEEWAY):
             raise AuthException(
                 self,
-                'Identity issued {0} seconds in the future'.format(
+                'Identity issued {} seconds in the future'.format(
                     issued_at - now
                 )
             )
@@ -157,7 +157,7 @@ def get_user_details(self, response):
         if identity['nonce'] != request_nonce:
             raise AuthException(
                 self,
-                'Replay attack detected: {0} != {1}'.format(
+                'Replay attack detected: {} != {}'.format(
                     identity['nonce'],
                     request_nonce
                 )
diff --git a/social_core/backends/mendeley.py b/social_core/backends/mendeley.py
index ebb73e66..e1619109 100644
--- a/social_core/backends/mendeley.py
+++ b/social_core/backends/mendeley.py
@@ -63,5 +63,5 @@ def get_user_data(self, access_token, *args, **kwargs):
         """Loads user data from service"""
         return self.get_json(
             'https://api.mendeley.com/profiles/me/',
-            headers={'Authorization': 'Bearer {0}'.format(access_token)}
+            headers={'Authorization': f'Bearer {access_token}'}
         )
diff --git a/social_core/backends/monzo.py b/social_core/backends/monzo.py
index 46b5ac63..c9b42706 100644
--- a/social_core/backends/monzo.py
+++ b/social_core/backends/monzo.py
@@ -28,5 +28,5 @@ def get_user_details(self, response):
     def user_data(self, access_token, *args, **kwargs):
         return self.get_json(
             'https://api.monzo.com/accounts',
-            headers={'Authorization': 'Bearer {0}'.format(access_token)},
+            headers={'Authorization': f'Bearer {access_token}'},
         )
diff --git a/social_core/backends/naver.py b/social_core/backends/naver.py
index 332f8132..df0ad295 100644
--- a/social_core/backends/naver.py
+++ b/social_core/backends/naver.py
@@ -27,7 +27,7 @@ def user_data(self, access_token, *args, **kwargs):
         response = self.request(
             'https://openapi.naver.com/v1/nid/me',
             headers={
-                'Authorization': 'Bearer {0}'.format(access_token),
+                'Authorization': f'Bearer {access_token}',
                 'Content_Type': 'text/json'
             }
         )
diff --git a/social_core/backends/oauth.py b/social_core/backends/oauth.py
index a2228244..c1b03b79 100644
--- a/social_core/backends/oauth.py
+++ b/social_core/backends/oauth.py
@@ -209,7 +209,7 @@ def get_unauthorized_token(self):
                 utoken = parse_qs(utoken)
             if utoken.get(self.OAUTH_TOKEN_PARAMETER_NAME) == data_token:
                 self.strategy.session_set(name, list(set(unauthed_tokens) -
-                                                     set([orig_utoken])))
+                                                     {orig_utoken}))
                 token = utoken
                 break
         else:
@@ -258,7 +258,7 @@ def oauth_authorization_request(self, token):
         )
         state = self.get_or_create_state()
         params[self.REDIRECT_URI_PARAMETER_NAME] = self.get_redirect_uri(state)
-        return '{0}?{1}'.format(self.authorization_url(), urlencode(params))
+        return f'{self.authorization_url()}?{urlencode(params)}'
 
     def oauth_auth(self, token=None, oauth_verifier=None,
                    signature_type=SIGNATURE_TYPE_AUTH_HEADER):
@@ -329,7 +329,7 @@ def auth_url(self):
             # redirect_uri matching is strictly enforced, so match the
             # providers value exactly.
             params = unquote(params)
-        return '{0}?{1}'.format(self.authorization_url(), params)
+        return f'{self.authorization_url()}?{params}'
 
     def auth_complete_params(self, state=None):
         client_id, client_secret = self.get_key_and_secret()
diff --git a/social_core/backends/odnoklassniki.py b/social_core/backends/odnoklassniki.py
index 03979c91..2b8c3848 100644
--- a/social_core/backends/odnoklassniki.py
+++ b/social_core/backends/odnoklassniki.py
@@ -51,8 +51,8 @@ class OdnoklassnikiApp(BaseAuth):
     ID_KEY = 'uid'
 
     def extra_data(self, user, uid, response, details=None, *args, **kwargs):
-        return dict([(key, value) for key, value in response.items()
-                     if key in response['extra_data_list']])
+        return {key: value for key, value in response.items()
+                     if key in response['extra_data_list']}
 
     def get_user_details(self, response):
         fullname, first_name, last_name = self.get_user_names(
@@ -75,7 +75,7 @@ def auth_complete(self, *args, **kwargs):
             self.setting('EXTRA_USER_DATA_LIST', ())
         data = {
             'method': 'users.getInfo',
-            'uids': '{0}'.format(response['logged_user_id']),
+            'uids': '{}'.format(response['logged_user_id']),
             'fields': ','.join(fields),
         }
         client_key, client_secret = self.get_key_and_secret()
@@ -100,7 +100,7 @@ def auth_complete(self, *args, **kwargs):
 
     def get_auth_sig(self):
         secret_key = self.setting('SECRET')
-        hash_source = '{0:s}{1:s}{2:s}'.format(self.data['logged_user_id'],
+        hash_source = '{:s}{:s}{:s}'.format(self.data['logged_user_id'],
                                                self.data['session_key'],
                                                secret_key)
         return md5(hash_source.encode('utf-8')).hexdigest()
@@ -109,8 +109,8 @@ def get_response(self):
         fields = ('logged_user_id', 'api_server', 'application_key',
                   'session_key', 'session_secret_key', 'authorized',
                   'apiconnection')
-        return dict((name, self.data[name]) for name in fields
-                    if name in self.data)
+        return {name: self.data[name] for name in fields
+                    if name in self.data}
 
     def verify_auth_sig(self):
         correct_key = self.get_auth_sig()
@@ -127,12 +127,12 @@ def odnoklassniki_oauth_sig(data, client_secret):
     search for "little bit different way"
     """
     suffix = md5(
-        '{0:s}{1:s}'.format(data['access_token'],
+        '{:s}{:s}'.format(data['access_token'],
                             client_secret).encode('utf-8')
     ).hexdigest()
-    check_list = sorted(['{0:s}={1:s}'.format(key, value)
+    check_list = sorted(f'{key:s}={value:s}'
                          for key, value in data.items()
-                         if key != 'access_token'])
+                         if key != 'access_token')
     return md5((''.join(check_list) + suffix).encode('utf-8')).hexdigest()
 
 
@@ -143,8 +143,8 @@ def odnoklassniki_iframe_sig(data, client_secret_or_session_secret):
     If API method requires session context, request is signed with session
     secret key. Otherwise it is signed with application secret key
     """
-    param_list = sorted(['{0:s}={1:s}'.format(key, value)
-                         for key, value in data.items()])
+    param_list = sorted(f'{key:s}={value:s}'
+                         for key, value in data.items())
     return md5(
         (''.join(param_list) + client_secret_or_session_secret).encode('utf-8')
     ).hexdigest()
diff --git a/social_core/backends/okta.py b/social_core/backends/okta.py
index b228e21f..d37e5f1c 100644
--- a/social_core/backends/okta.py
+++ b/social_core/backends/okta.py
@@ -24,7 +24,7 @@ def _url(self, path):
     def oidc_config(self):
         return self.get_json(
             self._url(
-                './.well-known/openid-configuration?client_id={}'.format(
+                '/.well-known/openid-configuration?client_id={}'.format(
                     self.setting('KEY')
                 )
             )
@@ -60,6 +60,6 @@ def user_data(self, access_token, *args, **kwargs):
         return self.get_json(
             self._url('v1/userinfo'),
             headers={
-                'Authorization': 'Bearer {}'.format(access_token),
+                'Authorization': f'Bearer {access_token}',
             }
         )
diff --git a/social_core/backends/open_id.py b/social_core/backends/open_id.py
index 38b217c6..063db2c6 100644
--- a/social_core/backends/open_id.py
+++ b/social_core/backends/open_id.py
@@ -239,7 +239,7 @@ def openid_request(self, params=None):
             return self.consumer().begin(url_add_parameters(self.openid_url(),
                                          params))
         except DiscoveryFailure as err:
-            raise AuthException(self, 'OpenID discovery error: {0}'.format(
+            raise AuthException(self, 'OpenID discovery error: {}'.format(
                 err
             ))
 
diff --git a/social_core/backends/open_id_connect.py b/social_core/backends/open_id_connect.py
index c770b934..3e678870 100644
--- a/social_core/backends/open_id_connect.py
+++ b/social_core/backends/open_id_connect.py
@@ -143,12 +143,28 @@ def validate_claims(self, id_token):
             raise AuthTokenError(self, 'Incorrect id_token: nonce')
 
     def find_valid_key(self, id_token):
-        for key in self.get_jwks_keys():
-            rsakey = jwk.construct(key)
-            message, encoded_sig = id_token.rsplit('.', 1)
-            decoded_sig = base64url_decode(encoded_sig.encode('utf-8'))
-            if rsakey.verify(message.encode('utf-8'), decoded_sig):
-                return key
+        kid = jwt.get_unverified_header(id_token).get('kid')
+
+        keys = self.get_jwks_keys()
+        if kid is not None:
+            for key in keys:
+                if kid == key.get('kid'):
+                    break
+            else:
+                # In case the key id is not found in the cached keys, just
+                # reload the JWKS keys. Ideally this should be done by
+                # invalidating the cache.
+                self.get_jwks_keys.invalidate()
+                keys = self.get_jwks_keys()
+
+        for key in keys:
+            if kid is None or kid == key.get('kid'):
+                rsakey = jwk.construct(key)
+                message, encoded_sig = id_token.rsplit('.', 1)
+                decoded_sig = base64url_decode(encoded_sig.encode('utf-8'))
+                if rsakey.verify(message.encode('utf-8'), decoded_sig):
+                    return key
+        return None
 
     def validate_and_return_id_token(self, id_token, access_token):
         """
@@ -199,7 +215,7 @@ def request_access_token(self, *args, **kwargs):
 
     def user_data(self, access_token, *args, **kwargs):
         return self.get_json(self.userinfo_url(), headers={
-            'Authorization': 'Bearer {0}'.format(access_token)
+            'Authorization': f'Bearer {access_token}'
         })
 
     def get_user_details(self, response):
diff --git a/social_core/backends/orcid.py b/social_core/backends/orcid.py
index fa68fd38..14ef280b 100644
--- a/social_core/backends/orcid.py
+++ b/social_core/backends/orcid.py
@@ -116,7 +116,7 @@ def user_data(self, access_token, *args, **kwargs):
                 self.USER_ID_URL,
                 headers={
                     'Content-Type': 'application/json',
-                    'Authorization': 'Bearer {}'.format(str(access_token))
+                    'Authorization': f'Bearer {str(access_token)}'
                 },
             )
 
diff --git a/social_core/backends/osso.py b/social_core/backends/osso.py
index 0fcbe8d7..a7c8a5b3 100644
--- a/social_core/backends/osso.py
+++ b/social_core/backends/osso.py
@@ -44,7 +44,7 @@ def get_user_details(self, response):
 
     def user_data(self, access_token, *args, **kwargs):
         """Loads normalized user profile from Osso"""
-        url = '{osso_base_url}/oauth/me?'.format(osso_base_url=self.osso_base_url) + urlencode({
+        url = f'{self.osso_base_url}/oauth/me?' + urlencode({
             'access_token': access_token
         })
         return self.get_json(url)
\ No newline at end of file
diff --git a/social_core/backends/patreon.py b/social_core/backends/patreon.py
index d0e0dc8d..ad5d8009 100644
--- a/social_core/backends/patreon.py
+++ b/social_core/backends/patreon.py
@@ -33,9 +33,9 @@ def user_data(self, access_token, *args, **kwargs):
 
     def get_api(self, access_token, suffix):
         return self.get_json(
-            'https://www.patreon.com/api/oauth2/v2/{}'.format(suffix),
+            f'https://www.patreon.com/api/oauth2/v2/{suffix}',
             headers=self.get_auth_header(access_token)
         )
 
     def get_auth_header(self, access_token):
-        return {'Authorization': 'Bearer {0}'.format(access_token)}
+        return {'Authorization': f'Bearer {access_token}'}
diff --git a/social_core/backends/phabricator.py b/social_core/backends/phabricator.py
index 1bd4ddc3..0a2eb9fe 100644
--- a/social_core/backends/phabricator.py
+++ b/social_core/backends/phabricator.py
@@ -16,7 +16,7 @@ class PhabricatorOAuth2(BaseOAuth2):
 
     def api_url(self, path):
         api_url = self.setting('API_URL') or self.API_URL
-        return '{0}{1}'.format(api_url.rstrip('/'), path)
+        return '{}{}'.format(api_url.rstrip('/'), path)
 
     def authorization_url(self):
         return self.api_url('/oauthserver/auth/')
diff --git a/social_core/backends/pinterest.py b/social_core/backends/pinterest.py
index eb5d2ce3..c28417d0 100644
--- a/social_core/backends/pinterest.py
+++ b/social_core/backends/pinterest.py
@@ -1,10 +1,8 @@
-# -*- coding: utf-8 -*-
 """
 Pinterest OAuth2 backend, docs at:
     https://developers.pinterest.com/docs/api/authentication/
 """
 
-from __future__ import unicode_literals
 
 import ssl
 
diff --git a/social_core/backends/pixelpin.py b/social_core/backends/pixelpin.py
index 3048134b..31b9c41f 100644
--- a/social_core/backends/pixelpin.py
+++ b/social_core/backends/pixelpin.py
@@ -30,6 +30,6 @@ def user_data(self, access_token, *args, **kwargs):
         return self.get_json(
             'https://login.pixelpin.io/connect/userinfo',
             headers={
-                'Authorization': 'Bearer {0}'.format(access_token)
+                'Authorization': f'Bearer {access_token}'
             }
         )
diff --git a/social_core/backends/professionali.py b/social_core/backends/professionali.py
index 15f39776..4e7e286c 100644
--- a/social_core/backends/professionali.py
+++ b/social_core/backends/professionali.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 Professionaly OAuth 2.0 support.
 
@@ -26,9 +25,9 @@ def get_user_details(self, response):
         first_name, last_name = map(response.get, ('firstname', 'lastname'))
         email = ''
         if self.setting('FAKE_EMAIL'):
-            email = '{0}@professionali.ru'.format(time())
+            email = f'{time()}@professionali.ru'
         return {
-            'username': '{0}_{1}'.format(last_name, first_name),
+            'username': f'{last_name}_{first_name}',
             'first_name': first_name,
             'last_name': last_name,
             'email': email
@@ -45,7 +44,7 @@ def user_data(self, access_token, response, *args, **kwargs):
         }
         try:
             return self.get_json(url, params)[0]
-        except (TypeError, KeyError, IOError, ValueError, IndexError):
+        except (TypeError, KeyError, OSError, ValueError, IndexError):
             return None
 
     def get_json(self, url, *args, **kwargs):
diff --git a/social_core/backends/pushbullet.py b/social_core/backends/pushbullet.py
index d821223f..d799fd1c 100644
--- a/social_core/backends/pushbullet.py
+++ b/social_core/backends/pushbullet.py
@@ -18,6 +18,6 @@ def get_user_details(self, response):
         return {'username': response.get('access_token')}
 
     def get_user_id(self, details, response):
-        auth = 'Basic {0}'.format(base64.b64encode(details['username']))
+        auth = 'Basic {}'.format(base64.b64encode(details['username']))
         return self.get_json('https://api.pushbullet.com/v2/users/me',
                              headers={'Authorization': auth})['iden']
diff --git a/social_core/backends/qiita.py b/social_core/backends/qiita.py
index 87fb6a40..e484448f 100644
--- a/social_core/backends/qiita.py
+++ b/social_core/backends/qiita.py
@@ -62,6 +62,6 @@ def user_data(self, access_token, *args, **kwargs):
         return self.get_json(
             'https://qiita.com/api/v2/authenticated_user',
             headers={
-                'Authorization': 'Bearer {0}'.format(access_token)
+                'Authorization': f'Bearer {access_token}'
             }
         )
diff --git a/social_core/backends/readability.py b/social_core/backends/readability.py
index 593117fc..b5adf79b 100644
--- a/social_core/backends/readability.py
+++ b/social_core/backends/readability.py
@@ -12,9 +12,9 @@ class ReadabilityOAuth(BaseOAuth1):
     """Readability OAuth authentication backend"""
     name = 'readability'
     ID_KEY = 'username'
-    AUTHORIZATION_URL = '{0}/oauth/authorize/'.format(READABILITY_API)
-    REQUEST_TOKEN_URL = '{0}/oauth/request_token/'.format(READABILITY_API)
-    ACCESS_TOKEN_URL = '{0}/oauth/access_token/'.format(READABILITY_API)
+    AUTHORIZATION_URL = f'{READABILITY_API}/oauth/authorize/'
+    REQUEST_TOKEN_URL = f'{READABILITY_API}/oauth/request_token/'
+    ACCESS_TOKEN_URL = f'{READABILITY_API}/oauth/access_token/'
     EXTRA_DATA = [('date_joined', 'date_joined'),
                   ('kindle_email_address', 'kindle_email_address'),
                   ('avatar_url', 'avatar_url'),
diff --git a/social_core/backends/reddit.py b/social_core/backends/reddit.py
index 97fa76b6..acd8102b 100644
--- a/social_core/backends/reddit.py
+++ b/social_core/backends/reddit.py
@@ -43,7 +43,7 @@ def user_data(self, access_token, *args, **kwargs):
     def auth_headers(self):
         return {
             'Authorization': b'Basic ' + base64.urlsafe_b64encode(
-                '{0}:{1}'.format(*self.get_key_and_secret()).encode()
+                '{}:{}'.format(*self.get_key_and_secret()).encode()
             )
         }
 
diff --git a/social_core/backends/runkeeper.py b/social_core/backends/runkeeper.py
index 18c2eec8..2bd3776b 100644
--- a/social_core/backends/runkeeper.py
+++ b/social_core/backends/runkeeper.py
@@ -43,5 +43,5 @@ def user_data(self, access_token, *args, **kwargs):
         return dict(user_data, **profile_data)
 
     def _user_data(self, access_token, path):
-        url = 'https://api.runkeeper.com{0}'.format(path)
+        url = f'https://api.runkeeper.com{path}'
         return self.get_json(url, params={'access_token': access_token})
diff --git a/social_core/backends/saml.py b/social_core/backends/saml.py
index c2902475..eb72e649 100644
--- a/social_core/backends/saml.py
+++ b/social_core/backends/saml.py
@@ -303,7 +303,7 @@ def get_user_id(self, details, response):
         """
         idp = self.get_idp(response['idp_name'])
         uid = idp.get_user_permanent_id(response['attributes'])
-        return '{0}:{1}'.format(idp.name, uid)
+        return f'{idp.name}:{uid}'
 
     def auth_complete(self, *args, **kwargs):
         """
@@ -318,7 +318,7 @@ def auth_complete(self, *args, **kwargs):
         if errors or not auth.is_authenticated():
             reason = auth.get_last_error_reason()
             raise AuthFailed(
-                self, 'SAML login failed: {0} ({1})'.format(errors, reason)
+                self, f'SAML login failed: {errors} ({reason})'
             )
 
         attributes = auth.get_attributes()
diff --git a/social_core/backends/shimmering.py b/social_core/backends/shimmering.py
index bc9a18c0..17650cf7 100644
--- a/social_core/backends/shimmering.py
+++ b/social_core/backends/shimmering.py
@@ -18,7 +18,7 @@ def get_user_details(self, response):
         last_name = response.get('last_name')
         email = response.get('email')
         username = response.get('username')
-        fullname = '{} {}'.format(first_name, last_name)
+        fullname = f'{first_name} {last_name}'
         return {
             'username': username,
             'fullname': fullname,
diff --git a/social_core/backends/shopify.py b/social_core/backends/shopify.py
index 9c8967d1..9f64c36b 100644
--- a/social_core/backends/shopify.py
+++ b/social_core/backends/shopify.py
@@ -91,7 +91,7 @@ def do_auth(self, access_token, shop_url, website, *args, **kwargs):
             'backend': self,
             'response': {
                 'shop': shop_url,
-                'website': 'http://{0}'.format(website),
+                'website': f'http://{website}',
                 'access_token': access_token
             }
         })
diff --git a/social_core/backends/sketchfab.py b/social_core/backends/sketchfab.py
index 5a8d0c6b..8b747a2a 100644
--- a/social_core/backends/sketchfab.py
+++ b/social_core/backends/sketchfab.py
@@ -35,5 +35,5 @@ def get_user_details(self, response):
     def user_data(self, access_token, *args, **kwargs):
         """Loads user data from service"""
         return self.get_json('https://sketchfab.com/v2/users/me', headers={
-            'Authorization': 'Bearer {0}'.format(access_token)
+            'Authorization': f'Bearer {access_token}'
         })
diff --git a/social_core/backends/slack.py b/social_core/backends/slack.py
index def02fbb..341654b2 100644
--- a/social_core/backends/slack.py
+++ b/social_core/backends/slack.py
@@ -3,7 +3,6 @@
     https://python-social-auth.readthedocs.io/en/latest/backends/slack.html
     https://api.slack.com/docs/oauth
 """
-from __future__ import unicode_literals
 
 from .oauth import BaseOAuth2
 
@@ -42,7 +41,7 @@ def get_user_details(self, response):
 
         if self.setting('USERNAME_WITH_TEAM', True) and team and \
            'name' in team:
-            username = '{0}@{1}'.format(username, response['team']['name'])
+            username = '{}@{}'.format(username, response['team']['name'])
 
         return {
             'username': username,
diff --git a/social_core/backends/spotify.py b/social_core/backends/spotify.py
index cc0e67e0..55c95a1e 100644
--- a/social_core/backends/spotify.py
+++ b/social_core/backends/spotify.py
@@ -22,10 +22,10 @@ class SpotifyOAuth2(BaseOAuth2):
     ]
 
     def auth_headers(self):
-        auth_str = '{0}:{1}'.format(*self.get_key_and_secret())
+        auth_str = '{}:{}'.format(*self.get_key_and_secret())
         b64_auth_str = base64.urlsafe_b64encode(auth_str.encode()).decode()
         return {
-            'Authorization': 'Basic {0}'.format(b64_auth_str)
+            'Authorization': f'Basic {b64_auth_str}'
         }
 
     def get_user_details(self, response):
@@ -43,5 +43,5 @@ def user_data(self, access_token, *args, **kwargs):
         """Loads user data from service"""
         return self.get_json(
             'https://api.spotify.com/v1/me',
-            headers={'Authorization': 'Bearer {0}'.format(access_token)}
+            headers={'Authorization': f'Bearer {access_token}'}
         )
diff --git a/social_core/backends/stripe.py b/social_core/backends/stripe.py
index 54d3cbd1..fe2e0a2c 100644
--- a/social_core/backends/stripe.py
+++ b/social_core/backends/stripe.py
@@ -39,7 +39,7 @@ def auth_complete_params(self, state=None):
     def auth_headers(self):
         client_id, client_secret = self.get_key_and_secret()
         return {'Accept': 'application/json',
-                'Authorization': 'Bearer {0}'.format(client_secret)}
+                'Authorization': f'Bearer {client_secret}'}
 
     def refresh_token_params(self, refresh_token, *args, **kwargs):
         return {'refresh_token': refresh_token,
diff --git a/social_core/backends/telegram.py b/social_core/backends/telegram.py
index e7f5d599..2f5077c8 100644
--- a/social_core/backends/telegram.py
+++ b/social_core/backends/telegram.py
@@ -23,7 +23,7 @@ def verify_data(self, response):
         if received_hash_string is None or auth_date is None:
             raise AuthMissingParameter('telegram', 'hash or auth_date')
 
-        data_check_string = ['{}={}'.format(k, v)
+        data_check_string = [f'{k}={v}'
                              for k, v in response.items() if k != 'hash']
         data_check_string = '\n'.join(sorted(data_check_string))
         secret_key = hashlib.sha256(bot_token.encode()).digest()
@@ -43,7 +43,7 @@ def extra_data(self, user, uid, response, details=None, *args, **kwargs):
     def get_user_details(self, response):
         first_name = response.get('first_name', '')
         last_name = response.get('last_name', '')
-        fullname = '{} {}'.format(first_name, last_name).strip()
+        fullname = f'{first_name} {last_name}'.strip()
         return {
             'username': response.get('username') or response[self.ID_KEY],
             'first_name': first_name,
diff --git a/social_core/backends/twilio.py b/social_core/backends/twilio.py
index 449c7726..756ad523 100644
--- a/social_core/backends/twilio.py
+++ b/social_core/backends/twilio.py
@@ -28,7 +28,7 @@ def auth_url(self):
         callback = self.strategy.absolute_uri(self.redirect_uri)
         callback = sub(r'^https', 'http', callback)
         query = urlencode({'cb': callback})
-        return 'https://www.twilio.com/authorize/{0}?{1}'.format(key, query)
+        return f'https://www.twilio.com/authorize/{key}?{query}'
 
     def auth_complete(self, *args, **kwargs):
         """Completes login process, must return user instance"""
diff --git a/social_core/backends/twitch.py b/social_core/backends/twitch.py
index aa555aae..a7222db2 100644
--- a/social_core/backends/twitch.py
+++ b/social_core/backends/twitch.py
@@ -3,6 +3,32 @@
     https://python-social-auth.readthedocs.io/en/latest/backends/twitch.html
 """
 from .oauth import BaseOAuth2
+from .open_id_connect import OpenIdConnectAuth
+
+
+class TwitchOpenIdConnect(OpenIdConnectAuth):
+    """Twitch OpenID Connect authentication backend"""
+    name = 'twitch'
+    USERNAME_KEY = 'preferred_username'
+    OIDC_ENDPOINT = 'https://id.twitch.tv/oauth2'
+    DEFAULT_SCOPE = ['openid', 'user:read:email']
+    TWITCH_CLAIMS = '{"id_token":{"email": null,"email_verified":null,"preferred_username":null}}'
+
+    def auth_params(self, state=None):
+        params = super().auth_params(state)
+        # Twitch uses a non-compliant OpenID implementation where the claims must be passed as a param
+        params['claims'] = self.TWITCH_CLAIMS
+        return params
+
+    def get_user_details(self, response):
+        return {
+            'username': self.id_token['preferred_username'],
+            'email': self.id_token['email'],
+            # Twitch does not provide this information
+            'fullname': '',
+            'first_name': '',
+            'last_name': '',
+        }
 
 
 class TwitchOAuth2(BaseOAuth2):
@@ -12,19 +38,31 @@ class TwitchOAuth2(BaseOAuth2):
     AUTHORIZATION_URL = 'https://id.twitch.tv/oauth2/authorize'
     ACCESS_TOKEN_URL = 'https://id.twitch.tv/oauth2/token'
     ACCESS_TOKEN_METHOD = 'POST'
-    DEFAULT_SCOPE = ['user_read']
+    DEFAULT_SCOPE = ['user:read:email']
     REDIRECT_STATE = False
 
+    def get_user_id(self, details, response):
+        """
+        Use twitch user id as unique id
+        """
+        return response.get('id')
+
     def get_user_details(self, response):
         return {
-            'username': response.get('name'),
+            'username': response.get('login'),
             'email': response.get('email'),
             'first_name': '',
             'last_name': ''
         }
 
     def user_data(self, access_token, *args, **kwargs):
-        return self.get_json(
-            'https://api.twitch.tv/kraken/user/',
-            params={'oauth_token': access_token, 'api_version': 5},
-        )
+        client_id, _ = self.get_key_and_secret()
+        auth_headers = {
+            'Authorization': 'Bearer %s' % access_token,
+            'Client-Id': client_id
+        }
+        url = 'https://api.twitch.tv/helix/users'
+
+        data = self.get_json(url, headers=auth_headers)
+
+        return data['data'][0] if data.get('data') else {}
diff --git a/social_core/backends/uber.py b/social_core/backends/uber.py
index 21bd9c51..b2aab2b3 100644
--- a/social_core/backends/uber.py
+++ b/social_core/backends/uber.py
@@ -34,6 +34,6 @@ def user_data(self, access_token, *args, **kwargs):
         """Loads user data from service"""
         response = kwargs.pop('response')
         return self.get_json('https://api.uber.com/v1/me', headers={
-            'Authorization': '{0} {1}'.format(response.get('token_type'),
+            'Authorization': '{} {}'.format(response.get('token_type'),
                                               access_token)
         })
diff --git a/social_core/backends/universe.py b/social_core/backends/universe.py
index c67e1c96..7869a801 100644
--- a/social_core/backends/universe.py
+++ b/social_core/backends/universe.py
@@ -31,5 +31,5 @@ def get_user_details(self, response):
     def user_data(self, access_token, *args, **kwargs):
         """Loads user data from service"""
         return self.get_json(self.USER_INFO_URL, headers={
-            'Authorization': 'Bearer {}'.format(access_token)
+            'Authorization': f'Bearer {access_token}'
         })
diff --git a/social_core/backends/upwork.py b/social_core/backends/upwork.py
index be68d0de..37f3e68a 100644
--- a/social_core/backends/upwork.py
+++ b/social_core/backends/upwork.py
@@ -22,7 +22,7 @@ def get_user_details(self, response):
         auth_user = response.get('auth_user', {})
         first_name = auth_user.get('first_name')
         last_name = auth_user.get('last_name')
-        fullname = '{} {}'.format(first_name, last_name)
+        fullname = f'{first_name} {last_name}'
         profile_url = info.get('profile_url', '')
         username = profile_url.rsplit('/')[-1].replace('~', '')
         return {
diff --git a/social_core/backends/utils.py b/social_core/backends/utils.py
index 9fbe51e0..88f143d0 100644
--- a/social_core/backends/utils.py
+++ b/social_core/backends/utils.py
@@ -76,7 +76,7 @@ def user_backends_data(user, backends, storage):
     if user_is_authenticated(user):
         associated = storage.user.get_social_auth_for_user(user)
         not_associated = list(set(available) -
-                              set(assoc.provider for assoc in associated))
+                              {assoc.provider for assoc in associated})
         values['associated'] = associated
         values['not_associated'] = not_associated
     return values
diff --git a/social_core/backends/vend.py b/social_core/backends/vend.py
index 99e45633..1ba046cc 100644
--- a/social_core/backends/vend.py
+++ b/social_core/backends/vend.py
@@ -32,8 +32,8 @@ def get_user_details(self, response):
     def user_data(self, access_token, *args, **kwargs):
         """Loads user data from service"""
         prefix = kwargs['response']['domain_prefix']
-        url = 'https://{0}.vendhq.com/api/users'.format(prefix)
+        url = f'https://{prefix}.vendhq.com/api/users'
         data = self.get_json(url, headers={
-            'Authorization': 'Bearer {0}'.format(access_token)
+            'Authorization': f'Bearer {access_token}'
         })
         return data['users'][0] if data.get('users') else {}
diff --git a/social_core/backends/vk.py b/social_core/backends/vk.py
index a3157b79..f751ec20 100644
--- a/social_core/backends/vk.py
+++ b/social_core/backends/vk.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 VK.com OpenAPI, OAuth2 and Iframe application OAuth2 backends, docs at:
     https://python-social-auth.readthedocs.io/en/latest/backends/vk.html
diff --git a/social_core/backends/weibo.py b/social_core/backends/weibo.py
index cb5dc908..da62dcd5 100644
--- a/social_core/backends/weibo.py
+++ b/social_core/backends/weibo.py
@@ -1,4 +1,3 @@
-# coding:utf-8
 # author:hepochen@gmail.com  https://github.com/hepochen
 """
 Weibo OAuth2 backend, docs at:
diff --git a/social_core/backends/weixin.py b/social_core/backends/weixin.py
index f68beb56..381de304 100644
--- a/social_core/backends/weixin.py
+++ b/social_core/backends/weixin.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 # author:duoduo3369@gmail.com  https://github.com/duoduo369
 """
 Weixin OAuth2 backend
diff --git a/social_core/backends/yahoo.py b/social_core/backends/yahoo.py
index d6ff380e..68bd2d90 100644
--- a/social_core/backends/yahoo.py
+++ b/social_core/backends/yahoo.py
@@ -102,7 +102,7 @@ def user_data(self, access_token, *args, **kwargs):
         url = 'https://api.login.yahoo.com/openid/v1/userinfo'
 
         return self.get_json(url, headers={
-            'Authorization': 'Bearer {0}'.format(access_token)
+            'Authorization': f'Bearer {access_token}'
         }, method='GET')
 
     @handle_http_errors
diff --git a/social_core/backends/zoom.py b/social_core/backends/zoom.py
index 3c68a725..e26b821b 100644
--- a/social_core/backends/zoom.py
+++ b/social_core/backends/zoom.py
@@ -54,7 +54,7 @@ def auth_complete_params(self, state=None):
     def auth_headers(self):
         return {
             'Authorization': b'Basic ' + base64.urlsafe_b64encode(
-                '{0}:{1}'.format(*self.get_key_and_secret()).encode()
+                '{}:{}'.format(*self.get_key_and_secret()).encode()
             )
         }
 
diff --git a/social_core/exceptions.py b/social_core/exceptions.py
index 461fefa2..d5b38ccf 100644
--- a/social_core/exceptions.py
+++ b/social_core/exceptions.py
@@ -8,14 +8,14 @@ def __init__(self, backend_name):
         self.backend_name = backend_name
 
     def __str__(self):
-        return 'Incorrect authentication service "{0}"'.format(
+        return 'Incorrect authentication service "{}"'.format(
             self.backend_name
         )
 
 
 class MissingBackend(WrongBackend):
     def __str__(self):
-        return 'Missing backend "{0}" entry'.format(self.backend_name)
+        return f'Missing backend "{self.backend_name}" entry'
 
 
 class NotAllowedToDisconnect(SocialAuthBaseException):
@@ -36,7 +36,7 @@ def __str__(self):
         msg = super().__str__()
         if msg == 'access_denied':
             return 'Authentication process was canceled'
-        return 'Authentication failed: {0}'.format(msg)
+        return f'Authentication failed: {msg}'
 
 
 class AuthCanceled(AuthException):
@@ -48,7 +48,7 @@ def __init__(self, *args, **kwargs):
     def __str__(self):
         msg = super().__str__()
         if msg:
-            return 'Authentication process canceled: {0}'.format(msg)
+            return f'Authentication process canceled: {msg}'
         return 'Authentication process canceled'
 
 
@@ -56,14 +56,14 @@ class AuthUnknownError(AuthException):
     """Unknown auth process error."""
     def __str__(self):
         msg = super().__str__()
-        return 'An unknown error happened while authenticating {0}'.format(msg)
+        return f'An unknown error happened while authenticating {msg}'
 
 
 class AuthTokenError(AuthException):
     """Auth token error."""
     def __str__(self):
         msg = super().__str__()
-        return 'Token error: {0}'.format(msg)
+        return f'Token error: {msg}'
 
 
 class AuthMissingParameter(AuthException):
@@ -73,7 +73,7 @@ def __init__(self, backend, parameter, *args, **kwargs):
         super().__init__(backend, *args, **kwargs)
 
     def __str__(self):
-        return 'Missing needed parameter {0}'.format(self.parameter)
+        return f'Missing needed parameter {self.parameter}'
 
 
 class AuthStateMissing(AuthException):
diff --git a/social_core/pipeline/user.py b/social_core/pipeline/user.py
index ef45ec08..f6cf14df 100644
--- a/social_core/pipeline/user.py
+++ b/social_core/pipeline/user.py
@@ -69,8 +69,8 @@ def create_user(strategy, details, backend, user=None, *args, **kwargs):
     if user:
         return {'is_new': False}
 
-    fields = dict((name, kwargs.get(name, details.get(name)))
-                  for name in backend.setting('USER_FIELDS', USER_FIELDS))
+    fields = {name: kwargs.get(name, details.get(name))
+                  for name in backend.setting('USER_FIELDS', USER_FIELDS)}
     if not fields:
         return
 
diff --git a/social_core/pipeline/utils.py b/social_core/pipeline/utils.py
index 112aed45..767e242f 100644
--- a/social_core/pipeline/utils.py
+++ b/social_core/pipeline/utils.py
@@ -63,6 +63,6 @@ def partial_load(strategy, token):
             kwargs['user'] = strategy.storage.user.get_user(user)
 
         partial.args = [strategy.from_session_value(val) for val in args]
-        partial.kwargs = dict((key, strategy.from_session_value(val))
-                              for key, val in kwargs.items())
+        partial.kwargs = {key: strategy.from_session_value(val)
+                              for key, val in kwargs.items()}
     return partial
diff --git a/social_core/storage.py b/social_core/storage.py
index f48a7cd9..2a2a5cbd 100644
--- a/social_core/storage.py
+++ b/social_core/storage.py
@@ -224,10 +224,10 @@ def oids(cls, server_url, handle=None):
         kwargs = {'server_url': server_url}
         if handle is not None:
             kwargs['handle'] = handle
-        return sorted([
+        return sorted((
             (assoc.id, cls.openid_association(assoc))
             for assoc in cls.get(**kwargs)
-        ], key=lambda x: x[1].issued, reverse=True)
+        ), key=lambda x: x[1].issued, reverse=True)
 
     @classmethod
     def openid_association(cls, assoc):
diff --git a/social_core/store.py b/social_core/store.py
index aa17223a..0851aed7 100644
--- a/social_core/store.py
+++ b/social_core/store.py
@@ -1,10 +1,6 @@
+import pickle
 import time
 
-try:
-    import cPickle as pickle
-except ImportError:
-    import pickle
-
 from openid.store.interface import OpenIDStore as BaseOpenIDStore
 from openid.store.nonce import SKEW
 
diff --git a/social_core/strategy.py b/social_core/strategy.py
index 9d7a7e59..4c0d74d4 100644
--- a/social_core/strategy.py
+++ b/social_core/strategy.py
@@ -116,7 +116,7 @@ def random_string(self, length=12, chars=ALLOWED_CHARS):
             random.SystemRandom()
         except NotImplementedError:
             key = self.setting('SECRET_KEY', '')
-            seed = '{0}{1}{2}'.format(random.getstate(), time.time(), key)
+            seed = f'{random.getstate()}{time.time()}{key}'
             random.seed(hashlib.sha256(seed.encode()).digest())
         return ''.join([random.choice(chars) for i in range(length)])
 
diff --git a/social_core/tests/backends/legacy.py b/social_core/tests/backends/legacy.py
index 45443cea..8393d3ba 100644
--- a/social_core/tests/backends/legacy.py
+++ b/social_core/tests/backends/legacy.py
@@ -13,14 +13,14 @@ class BaseLegacyTest(BaseBackendTest):
     def setUp(self):
         super().setUp()
         self.strategy.set_settings({
-            'SOCIAL_AUTH_{0}_FORM_URL'.format(self.name):
-                self.strategy.build_absolute_uri('/login/{0}'.format(
+            f'SOCIAL_AUTH_{self.name}_FORM_URL':
+                self.strategy.build_absolute_uri('/login/{}'.format(
                     self.backend.name))
         })
 
     def extra_settings(self):
-        return {'SOCIAL_AUTH_{0}_FORM_URL'.format(self.name):
-                '/login/{0}'.format(self.backend.name)}
+        return {f'SOCIAL_AUTH_{self.name}_FORM_URL':
+                f'/login/{self.backend.name}'}
 
     def do_start(self):
         start_url = self.strategy.build_absolute_uri(self.backend.start().url)
diff --git a/social_core/tests/backends/oauth.py b/social_core/tests/backends/oauth.py
index 9058a8ed..0f04b2bd 100644
--- a/social_core/tests/backends/oauth.py
+++ b/social_core/tests/backends/oauth.py
@@ -58,11 +58,6 @@ def auth_handlers(self, start_url):
                                target_url,
                                status=200,
                                body='foobar')
-        HTTPretty.register_uri(self._method(self.backend.ACCESS_TOKEN_METHOD),
-                               uri=self.backend.access_token_url(),
-                               status=self.access_token_status,
-                               body=self.access_token_body or '',
-                               content_type='text/json')
         if self.user_data_url:
             HTTPretty.register_uri(HTTPretty.POST if self.user_data_url_post else HTTPretty.GET,
                                    self.user_data_url,
@@ -70,6 +65,13 @@ def auth_handlers(self, start_url):
                                    content_type=self.user_data_content_type)
         return target_url
 
+    def pre_complete_callback(self, start_url):
+        HTTPretty.register_uri(self._method(self.backend.ACCESS_TOKEN_METHOD),
+                               uri=self.backend.access_token_url(),
+                               status=self.access_token_status,
+                               body=self.access_token_body or '',
+                               content_type='text/json')
+
     def do_start(self):
         start_url = self.backend.start().url
         target_url = self.auth_handlers(start_url)
@@ -80,6 +82,7 @@ def do_start(self):
                                        self.backend)
         self.strategy.set_request_data(parse_qs(urlparse(target_url).query),
                                        self.backend)
+        self.pre_complete_callback(start_url)
         return self.backend.complete()
 
 
diff --git a/social_core/tests/backends/open_id.py b/social_core/tests/backends/open_id.py
index 8a4efdf3..75b75bc8 100644
--- a/social_core/tests/backends/open_id.py
+++ b/social_core/tests/backends/open_id.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 import sys
 from html.parser import HTMLParser
 
diff --git a/social_core/tests/backends/test_auth0.py b/social_core/tests/backends/test_auth0.py
index 3f40a18e..332f4535 100644
--- a/social_core/tests/backends/test_auth0.py
+++ b/social_core/tests/backends/test_auth0.py
@@ -1,4 +1,3 @@
-
 import json
 
 from jose import jwt
@@ -43,7 +42,7 @@ class Auth0OAuth2Test(OAuth2Test):
             'name': 'John Doe',
             'picture': 'http://example.com/image.png',
             'sub': '123456',
-            'iss': 'https://{}/'.format(DOMAIN),
+            'iss': f'https://{DOMAIN}/',
         }, JWK_KEY, algorithm='RS256')
     })
     expected_username = 'foobar'
diff --git a/social_core/tests/backends/test_bitbucket.py b/social_core/tests/backends/test_bitbucket.py
index 263f6419..14818f93 100644
--- a/social_core/tests/backends/test_bitbucket.py
+++ b/social_core/tests/backends/test_bitbucket.py
@@ -13,41 +13,41 @@ class BitbucketOAuthMixin:
     bb_api_user_emails = 'https://api.bitbucket.org/2.0/user/emails'
 
     user_data_body = json.dumps({
-        u'created_on': u'2012-03-29T18:07:38+00:00',
-        u'display_name': u'Foo Bar',
-        u'links': {
-            u'avatar': {u'href': u'https://bitbucket.org/account/foobar/avatar/32/'},
-            u'followers': {u'href': u'https://api.bitbucket.org/2.0/users/foobar/followers'},
-            u'following': {u'href': u'https://api.bitbucket.org/2.0/users/foobar/following'},
-            u'hooks': {u'href': u'https://api.bitbucket.org/2.0/users/foobar/hooks'},
-            u'html': {u'href': u'https://bitbucket.org/foobar'},
-            u'repositories': {u'href': u'https://api.bitbucket.org/2.0/repositories/foobar'},
-            u'self': {u'href': u'https://api.bitbucket.org/2.0/users/foobar'}},
-        u'location': u'Fooville, Bar',
-        u'type': u'user',
-        u'username': u'foobar',
-        u'uuid': u'{397621dc-0f78-329f-8d6d-727396248e3f}',
-        u'website': u'http://foobar.com'
+        'created_on': '2012-03-29T18:07:38+00:00',
+        'display_name': 'Foo Bar',
+        'links': {
+            'avatar': {'href': 'https://bitbucket.org/account/foobar/avatar/32/'},
+            'followers': {'href': 'https://api.bitbucket.org/2.0/users/foobar/followers'},
+            'following': {'href': 'https://api.bitbucket.org/2.0/users/foobar/following'},
+            'hooks': {'href': 'https://api.bitbucket.org/2.0/users/foobar/hooks'},
+            'html': {'href': 'https://bitbucket.org/foobar'},
+            'repositories': {'href': 'https://api.bitbucket.org/2.0/repositories/foobar'},
+            'self': {'href': 'https://api.bitbucket.org/2.0/users/foobar'}},
+        'location': 'Fooville, Bar',
+        'type': 'user',
+        'username': 'foobar',
+        'uuid': '{397621dc-0f78-329f-8d6d-727396248e3f}',
+        'website': 'http://foobar.com'
     })
 
     emails_body = json.dumps({
-        u'page': 1,
-        u'pagelen': 10,
-        u'size': 2,
-        u'values': [
+        'page': 1,
+        'pagelen': 10,
+        'size': 2,
+        'values': [
             {
-                u'email': u'foo@bar.com',
-                u'is_confirmed': True,
-                u'is_primary': True,
-                u'links': {u'self': {u'href': u'https://api.bitbucket.org/2.0/user/emails/foo@bar.com'}},
-                u'type': u'email'
+                'email': 'foo@bar.com',
+                'is_confirmed': True,
+                'is_primary': True,
+                'links': {'self': {'href': 'https://api.bitbucket.org/2.0/user/emails/foo@bar.com'}},
+                'type': 'email'
             },
             {
-                u'email': u'not@confirme.com',
-                u'is_confirmed': False,
-                u'is_primary': False,
-                u'links': {u'self': {u'href': u'https://api.bitbucket.org/2.0/user/emails/not@confirmed.com'}},
-                u'type': u'email'
+                'email': 'not@confirme.com',
+                'is_confirmed': False,
+                'is_primary': False,
+                'links': {'self': {'href': 'https://api.bitbucket.org/2.0/user/emails/not@confirmed.com'}},
+                'type': 'email'
             }
         ]
     })
@@ -82,16 +82,16 @@ def test_partial_pipeline(self):
 
 class BitbucketOAuth1FailTest(BitbucketOAuth1Test):
     emails_body = json.dumps({
-        u'page': 1,
-        u'pagelen': 10,
-        u'size': 1,
-        u'values': [
+        'page': 1,
+        'pagelen': 10,
+        'size': 1,
+        'values': [
             {
-                u'email': u'foo@bar.com',
-                u'is_confirmed': False,
-                u'is_primary': True,
-                u'links': {u'self': {u'href': u'https://api.bitbucket.org/2.0/user/emails/foo@bar.com'}},
-                u'type': u'email'
+                'email': 'foo@bar.com',
+                'is_confirmed': False,
+                'is_primary': True,
+                'links': {'self': {'href': 'https://api.bitbucket.org/2.0/user/emails/foo@bar.com'}},
+                'type': 'email'
             }
         ]
     })
@@ -137,16 +137,16 @@ def test_partial_pipeline(self):
 
 class BitbucketOAuth2FailTest(BitbucketOAuth2Test):
     emails_body = json.dumps({
-        u'page': 1,
-        u'pagelen': 10,
-        u'size': 1,
-        u'values': [
+        'page': 1,
+        'pagelen': 10,
+        'size': 1,
+        'values': [
             {
-                u'email': u'foo@bar.com',
-                u'is_confirmed': False,
-                u'is_primary': True,
-                u'links': {u'self': {u'href': u'https://api.bitbucket.org/2.0/user/emails/foo@bar.com'}},
-                u'type': u'email'
+                'email': 'foo@bar.com',
+                'is_confirmed': False,
+                'is_primary': True,
+                'links': {'self': {'href': 'https://api.bitbucket.org/2.0/user/emails/foo@bar.com'}},
+                'type': 'email'
             }
         ]
     })
diff --git a/social_core/tests/backends/test_discourse.py b/social_core/tests/backends/test_discourse.py
index 458f8b9f..43524904 100644
--- a/social_core/tests/backends/test_discourse.py
+++ b/social_core/tests/backends/test_discourse.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 from urllib.parse import urlparse, parse_qs
 
 import requests
@@ -36,9 +35,9 @@ def do_start(self):
         # NOTE: the signature was verified using the 'foo' key, like so:
         # hmac.new('foo', sso, sha256).hexdigest()
         sig = '04063f17c99a97b1a765c1e0d7bbb61afb8471d79a39ddcd6af5ba3c93eb10e1'
-        response_query_params = 'sso={0}&sig={1}'.format(sso, sig)
+        response_query_params = f'sso={sso}&sig={sig}'
 
-        response_url = '{0}?{1}'.format(return_url, response_query_params)
+        response_url = f'{return_url}?{response_query_params}'
         HTTPretty.register_uri(
             HTTPretty.GET, start_url, status=301, location=response_url
         )
@@ -50,9 +49,9 @@ def do_start(self):
         )
 
         response = requests.get(start_url)
-        query_values = dict(
-            (k, v[0]) for k, v in parse_qs(urlparse(response.url).query).items()
-        )
+        query_values = {
+            k: v[0] for k, v in parse_qs(urlparse(response.url).query).items()
+        }
         self.strategy.set_request_data(query_values, self.backend)
 
         return self.backend.complete()
diff --git a/social_core/tests/backends/test_elixir.py b/social_core/tests/backends/test_elixir.py
index 766c76be..28b726d8 100644
--- a/social_core/tests/backends/test_elixir.py
+++ b/social_core/tests/backends/test_elixir.py
@@ -1,5 +1,5 @@
 from .oauth import OAuth2Test
-from .open_id_connect import OpenIdConnectTestMixin
+from .test_open_id_connect import OpenIdConnectTestMixin
 
 
 class ElixirOpenIdConnectTest(OpenIdConnectTestMixin, OAuth2Test):
diff --git a/social_core/tests/backends/test_fence.py b/social_core/tests/backends/test_fence.py
index 24a8362e..ed8b0aaf 100644
--- a/social_core/tests/backends/test_fence.py
+++ b/social_core/tests/backends/test_fence.py
@@ -1,7 +1,7 @@
 import json
 
 from .oauth import OAuth2Test
-from .open_id_connect import OpenIdConnectTestMixin
+from .test_open_id_connect import OpenIdConnectTestMixin
 
 
 class FenceOpenIdConnectTest(OpenIdConnectTestMixin, OAuth2Test):
diff --git a/social_core/tests/backends/test_globus.py b/social_core/tests/backends/test_globus.py
index d9381bcc..443607e4 100644
--- a/social_core/tests/backends/test_globus.py
+++ b/social_core/tests/backends/test_globus.py
@@ -1,7 +1,7 @@
 import json
 
 from .oauth import OAuth2Test
-from .open_id_connect import OpenIdConnectTestMixin
+from .test_open_id_connect import OpenIdConnectTestMixin
 
 
 class GlobusOpenIdConnectTest(OpenIdConnectTestMixin, OAuth2Test):
diff --git a/social_core/tests/backends/test_google.py b/social_core/tests/backends/test_google.py
index e3c7b58a..701af100 100644
--- a/social_core/tests/backends/test_google.py
+++ b/social_core/tests/backends/test_google.py
@@ -7,7 +7,7 @@
 
 from ..models import User
 from .oauth import OAuth1Test, OAuth2Test
-from .open_id_connect import OpenIdConnectTestMixin
+from .test_open_id_connect import OpenIdConnectTestMixin
 
 
 class GoogleOAuth2Test(OAuth2Test):
diff --git a/social_core/tests/backends/test_ngpvan.py b/social_core/tests/backends/test_ngpvan.py
index 50e940e9..d0b13e46 100644
--- a/social_core/tests/backends/test_ngpvan.py
+++ b/social_core/tests/backends/test_ngpvan.py
@@ -170,12 +170,12 @@ def test_user_data(self):
             ]
         })
         user = self.do_start()
-        self.assertEqual(user.username, u'testuser@user.local')
-        self.assertEqual(user.email, u'testuser@user.local')
-        self.assertEqual(user.extra_user_fields['phone'], u'+12015555555')
-        self.assertEqual(user.extra_user_fields['first_name'], u'John')
-        self.assertEqual(user.extra_user_fields['last_name'], u'Smith')
-        self.assertEqual(user.extra_user_fields['fullname'], u'John Smith')
+        self.assertEqual(user.username, 'testuser@user.local')
+        self.assertEqual(user.email, 'testuser@user.local')
+        self.assertEqual(user.extra_user_fields['phone'], '+12015555555')
+        self.assertEqual(user.extra_user_fields['first_name'], 'John')
+        self.assertEqual(user.extra_user_fields['last_name'], 'Smith')
+        self.assertEqual(user.extra_user_fields['fullname'], 'John Smith')
 
     def test_extra_data_phone(self):
         """Confirm that you can get a phone number via the relevant setting"""
@@ -185,7 +185,7 @@ def test_extra_data_phone(self):
             ]
         })
         user = self.do_start()
-        self.assertEqual(user.social_user.extra_data['phone'], u'+12015555555')
+        self.assertEqual(user.social_user.extra_data['phone'], '+12015555555')
 
     def test_association_uid(self):
         """Test that the correct association uid is stored in the database"""
diff --git a/social_core/tests/backends/test_okta.py b/social_core/tests/backends/test_okta.py
index 4762851c..16526cbd 100644
--- a/social_core/tests/backends/test_okta.py
+++ b/social_core/tests/backends/test_okta.py
@@ -2,7 +2,7 @@
 from httpretty import HTTPretty
 
 from social_core.tests.backends.oauth import OAuth2Test
-from social_core.tests.backends.open_id_connect import OpenIdConnectTestMixin
+from social_core.tests.backends.test_open_id_connect import OpenIdConnectTestMixin
 
 JWK_KEY = {
     'kty': 'RSA',
diff --git a/social_core/tests/backends/open_id_connect.py b/social_core/tests/backends/test_open_id_connect.py
similarity index 72%
rename from social_core/tests/backends/open_id_connect.py
rename to social_core/tests/backends/test_open_id_connect.py
index 6731039e..928571f3 100644
--- a/social_core/tests/backends/open_id_connect.py
+++ b/social_core/tests/backends/test_open_id_connect.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 from ...exceptions import AuthTokenError
 import os
 import sys
@@ -6,10 +5,16 @@
 import datetime
 import base64
 from calendar import timegm
+from unittest import mock
+from urllib.parse import urlparse
 
 from jose import jwt
 from httpretty import HTTPretty
 
+from social_core.backends.open_id_connect import OpenIdConnectAuth
+from ...utils import parse_qs
+from .oauth import OAuth2Test
+
 
 sys.path.insert(0, '..')
 
@@ -49,6 +54,7 @@ class OpenIdConnectTestMixin:
     issuer = None  # id_token issuer
     openid_config_body = None
     key = None
+    access_token_kwargs = {}
 
     def setUp(self):
         super().setUp()
@@ -73,9 +79,9 @@ def jwks(_request, _uri, headers):
     def extra_settings(self):
         settings = super().extra_settings()
         settings.update({
-            'SOCIAL_AUTH_{0}_KEY'.format(self.name): self.client_key,
-            'SOCIAL_AUTH_{0}_SECRET'.format(self.name): self.client_secret,
-            'SOCIAL_AUTH_{0}_ID_TOKEN_DECRYPTION_KEY'.format(self.name):
+            f'SOCIAL_AUTH_{self.name}_KEY': self.client_key,
+            f'SOCIAL_AUTH_{self.name}_SECRET': self.client_secret,
+            f'SOCIAL_AUTH_{self.name}_ID_TOKEN_DECRYPTION_KEY':
                 self.client_secret
         })
         return settings
@@ -96,7 +102,7 @@ def get_id_token(self, client_key=None, expiration_datetime=None,
         }
 
     def prepare_access_token_body(self, client_key=None, tamper_message=False,
-                                  expiration_datetime=None,
+                                  expiration_datetime=None, kid=None,
                                   issue_datetime=None, nonce=None,
                                   issuer=None):
         """
@@ -125,12 +131,13 @@ def prepare_access_token_body(self, client_key=None, tamper_message=False,
         )
 
         body['id_token'] = jwt.encode(
-            id_token,
+            claims=id_token,
             key=dict(self.key,
                      iat=timegm(issue_datetime.utctimetuple()),
                      nonce=nonce),
             algorithm='RS256',
-            access_token='foobar'
+            access_token='foobar',
+            headers=dict(kid=kid),
         )
 
         if tamper_message:
@@ -142,12 +149,20 @@ def prepare_access_token_body(self, client_key=None, tamper_message=False,
         return json.dumps(body)
 
     def authtoken_raised(self, expected_message, **access_token_kwargs):
-        self.access_token_body = self.prepare_access_token_body(
-            **access_token_kwargs
-        )
+        self.access_token_kwargs = access_token_kwargs
         with self.assertRaisesRegex(AuthTokenError, expected_message):
             self.do_login()
 
+    def pre_complete_callback(self, start_url):
+        nonce = parse_qs(urlparse(start_url).query)['nonce']
+
+        self.access_token_kwargs.setdefault('nonce', nonce)
+        self.access_token_body = self.prepare_access_token_body(
+            **self.access_token_kwargs
+        )
+        super().pre_complete_callback(start_url)
+
+
     def test_invalid_signature(self):
         self.authtoken_raised(
             'Token error: Signature verification failed',
@@ -177,5 +192,41 @@ def test_invalid_issue_time(self):
     def test_invalid_nonce(self):
         self.authtoken_raised(
             'Token error: Incorrect id_token: nonce',
-            nonce='something-wrong'
+            nonce='something-wrong',
+            kid='testkey',
         )
+
+    def test_invalid_kid(self):
+        self.authtoken_raised('Token error: Signature verification failed', kid='doesnotexist')
+
+
+class ExampleOpenIdConnectAuth(OpenIdConnectAuth):
+    name = 'example123'
+    OIDC_ENDPOINT = 'https://example.com/oidc'
+
+
+class OpenIdConnectTest(OpenIdConnectTestMixin, OAuth2Test):
+    backend_path = \
+        'social_core.tests.backends.test_open_id_connect.ExampleOpenIdConnectAuth'
+    issuer = 'https://example.com'
+    openid_config_body = json.dumps({
+        'issuer': 'https://example.com',
+        'authorization_endpoint': 'https://example.com/oidc/auth',
+        'token_endpoint': 'https://example.com/oidc/token',
+        'userinfo_endpoint': 'https://example.com/oidc/userinfo',
+        'revocation_endpoint': 'https://example.com/oidc/revoke',
+        'jwks_uri': 'https://example.com/oidc/certs',
+    })
+
+    expected_username = 'cartman'
+
+    def pre_complete_callback(self, start_url):
+        super().pre_complete_callback(start_url)
+        HTTPretty.register_uri('GET',
+                               uri=self.backend.userinfo_url(),
+                               status=200,
+                               body=json.dumps({'preferred_username': self.expected_username}),
+                               content_type='text/json')
+
+    def test_everything_works(self):
+        self.do_login()
diff --git a/social_core/tests/backends/test_saml.py b/social_core/tests/backends/test_saml.py
index 85e57949..40a0837f 100644
--- a/social_core/tests/backends/test_saml.py
+++ b/social_core/tests/backends/test_saml.py
@@ -1,4 +1,3 @@
-
 import json
 import os
 import re
@@ -36,7 +35,7 @@ class SAMLTest(BaseBackendTest):
 
     def extra_settings(self):
         name = path.join(DATA_DIR, 'saml_config.json')
-        with open(name, 'r') as config_file:
+        with open(name) as config_file:
             config_str = config_file.read()
         return json.loads(config_str)
 
@@ -61,7 +60,7 @@ def install_http_intercepts(self, start_url, return_url):
         # data in the query string.  A pre-recorded correct response
         # is kept in this .txt file:
         name = path.join(DATA_DIR, 'saml_response.txt')
-        with open(name, 'r') as response_file:
+        with open(name) as response_file:
             response_url = response_file.read()
         HTTPretty.register_uri(HTTPretty.GET, start_url, status=301,
                                location=response_url)
@@ -80,8 +79,8 @@ def do_start(self):
         response = requests.get(start_url)
         self.assertTrue(response.url.startswith(return_url))
         self.assertEqual(response.text, 'foobar')
-        query_values = dict((k, v[0]) for k, v in
-                            parse_qs(urlparse(response.url).query).items())
+        query_values = {k: v[0] for k, v in
+                            parse_qs(urlparse(response.url).query).items()}
         self.assertNotIn(' ', query_values['SAMLResponse'])
         self.strategy.set_request_data(query_values, self.backend)
         return self.backend.complete()
@@ -110,8 +109,8 @@ def modify_start_url(self, start_url):
         """
         # Parse the SAML Request URL to get the XML being sent to TestShib
         url_parts = urlparse(start_url)
-        query = dict((k, v[0]) for (k, v) in
-                     parse_qs(url_parts.query).items())
+        query = {k: v[0] for (k, v) in
+                     parse_qs(url_parts.query).items()}
         xml = OneLogin_Saml2_Utils.decode_base64_and_inflate(
             query['SAMLRequest']
         )
diff --git a/social_core/tests/backends/test_slack.py b/social_core/tests/backends/test_slack.py
index 7055f574..f73f8e5c 100644
--- a/social_core/tests/backends/test_slack.py
+++ b/social_core/tests/backends/test_slack.py
@@ -15,12 +15,12 @@ class SlackOAuth2Test(OAuth2Test):
         'user': {
             'email': 'foobar@example.com',
             'name': 'Foo Bar',
-            'id': u'123456'
+            'id': '123456'
         },
         'team': {
-            'id': u'456789'
+            'id': '456789'
         },
-        'scope': u'identity.basic,identity.email'
+        'scope': 'identity.basic,identity.email'
     })
     expected_username = 'foobar'
 
@@ -38,13 +38,13 @@ class SlackOAuth2TestTeamName(SlackOAuth2Test):
         'user': {
             'email': 'foobar@example.com',
             'name': 'Foo Bar',
-            'id': u'123456'
+            'id': '123456'
         },
         'team': {
-            'id': u'456789',
-            'name': u'Square',
+            'id': '456789',
+            'name': 'Square',
         },
-        'scope': u'identity.basic,identity.email,identity.team'
+        'scope': 'identity.basic,identity.email,identity.team'
     })
 
 
@@ -54,13 +54,13 @@ class SlackOAuth2TestUnicodeTeamName(SlackOAuth2Test):
         'user': {
             'email': 'foobar@example.com',
             'name': 'Foo Bar',
-            'id': u'123456'
+            'id': '123456'
         },
         'team': {
-            'id': u'456789',
-            'name': u'Square \u221a team',
+            'id': '456789',
+            'name': 'Square \u221a team',
         },
-        'scope': u'identity.basic,identity.email,identity.team'
+        'scope': 'identity.basic,identity.email,identity.team'
     })
 
     def test_login(self):
diff --git a/social_core/tests/backends/test_twitch.py b/social_core/tests/backends/test_twitch.py
index 67b1e375..2907f809 100644
--- a/social_core/tests/backends/test_twitch.py
+++ b/social_core/tests/backends/test_twitch.py
@@ -1,32 +1,80 @@
 import json
 from .oauth import OAuth2Test
+from .test_open_id_connect import OpenIdConnectTestMixin
+
+
+class TwitchOpenIdConnectTest(OpenIdConnectTestMixin, OAuth2Test):
+    backend_path = 'social_core.backends.twitch.TwitchOpenIdConnect'
+    user_data_url = 'https://id.twitch.tv/oauth2/userinfo'
+    issuer = 'https://id.twitch.tv/oauth2'
+    expected_username = 'test_user1'
+    openid_config_body = json.dumps({
+        'authorization_endpoint': 'https://id.twitch.tv/oauth2/authorize',
+        'claims_parameter_supported': True,
+        'claims_supported': [
+            'iss',
+            'azp',
+            'preferred_username',
+            'updated_at',
+            'aud',
+            'exp',
+            'iat',
+            'picture',
+            'sub',
+            'email',
+            'email_verified',
+        ],
+        'id_token_signing_alg_values_supported': [
+            'RS256',
+        ],
+        'issuer': 'https://id.twitch.tv/oauth2',
+        'jwks_uri': 'https://id.twitch.tv/oauth2/keys',
+        'response_types_supported': [
+            'id_token',
+            'code',
+            'token',
+            'code id_token',
+            'token id_token',
+        ],
+        'scopes_supported': [
+            'openid',
+        ],
+        'subject_types_supported': [
+            'public',
+        ],
+        'token_endpoint': 'https://id.twitch.tv/oauth2/token',
+        'token_endpoint_auth_methods_supported': [
+            'client_secret_post',
+        ],
+        'userinfo_endpoint': 'https://id.twitch.tv/oauth2/userinfo',
+    })
 
 
 class TwitchOAuth2Test(OAuth2Test):
     backend_path = 'social_core.backends.twitch.TwitchOAuth2'
-    user_data_url = 'https://api.twitch.tv/kraken/user/'
+    user_data_url = 'https://api.twitch.tv/helix/users'
     expected_username = 'test_user1'
     access_token_body = json.dumps({
         'access_token': 'foobar',
+        'token_type': 'bearer',
     })
     user_data_body = json.dumps({
-        'type': 'user',
-        'name': 'test_user1',
-        'created_at': '2011-06-03T17:49:19Z',
-        'updated_at': '2012-06-18T17:19:57Z',
-        'logo': 'http://static-cdn.jtvnw.net/jtv_user_pictures/'
-                'test_user1-profile_image-62e8318af864d6d7-300x300.jpeg',
-        '_id': 22761313,
-        'display_name': 'test_user1',
-        'bio': 'test bio woo I\'m a test user',
-        'email': 'asdf@asdf.com',
-        'email_verified': True,
-        'partnered': True,
-        'twitter_connected': False,
-        'notifications': {
-            'push': True,
-            'email': True
-        }
+        'data': [
+            {
+                'id': '689563726',
+                'login': 'test_user1',
+                'display_name': 'test_user1',
+                'type': '',
+                'broadcaster_type': '',
+                'description': '',
+                'profile_image_url': 'https://static-cdn.jtvnw.net/jtv_user_pictures/foo.png',
+                'offline_image_url': '',
+                'view_count': 0,
+                'email': 'example@reply.com',
+                'created_at': '2021-05-21T18:59:25Z',
+                'access_token': 'hmkgz15x7j54jm63rpwfwhcnue6t4fxwv'
+            }
+        ]
     })
 
     def test_login(self):
diff --git a/social_core/tests/backends/test_vk.py b/social_core/tests/backends/test_vk.py
index 606b899d..6d8c2279 100644
--- a/social_core/tests/backends/test_vk.py
+++ b/social_core/tests/backends/test_vk.py
@@ -1,6 +1,3 @@
-# coding: utf-8
-from __future__ import unicode_literals
-
 import json
 
 from .oauth import OAuth2Test
diff --git a/social_core/tests/test_partial.py b/social_core/tests/test_partial.py
index b5ae3c49..67439c73 100644
--- a/social_core/tests/test_partial.py
+++ b/social_core/tests/test_partial.py
@@ -17,8 +17,8 @@ def setUp(self):
         self.mock_partial_store = Mock()
         self.mock_strategy.storage.partial.store = self.mock_partial_store
 
-        self.mock_sesstion_set = Mock()
-        self.mock_strategy.session_set = self.mock_sesstion_set
+        self.mock_session_set = Mock()
+        self.mock_strategy.session_set = self.mock_session_set
 
     def test_save_to_session(self):
         # GIVEN
@@ -42,10 +42,10 @@ def decorated_func(*args, **kwargs):
             self.assertEqual((self.mock_current_partial,),
                              self.mock_partial_store.call_args[0])
 
-            self.assertEqual(1, self.mock_sesstion_set.call_count)
+            self.assertEqual(1, self.mock_session_set.call_count)
             self.assertEqual((PARTIAL_TOKEN_SESSION_NAME,
                               self.mock_current_partial_token),
-                             self.mock_sesstion_set.call_args[0])
+                             self.mock_session_set.call_args[0])
 
     def test_not_to_save_to_session(self):
         # GIVEN
@@ -69,7 +69,7 @@ def decorated_func(*args, **kwargs):
             self.assertEqual((self.mock_current_partial,),
                              self.mock_partial_store.call_args[0])
 
-            self.assertEqual(0, self.mock_sesstion_set.call_count)
+            self.assertEqual(0, self.mock_session_set.call_count)
 
     def test_save_to_session_by_backward_compatible_decorator(self):
         # GIVEN
@@ -93,10 +93,10 @@ def decorated_func(*args, **kwargs):
             self.assertEqual((self.mock_current_partial,),
                              self.mock_partial_store.call_args[0])
 
-            self.assertEqual(1, self.mock_sesstion_set.call_count)
+            self.assertEqual(1, self.mock_session_set.call_count)
             self.assertEqual((PARTIAL_TOKEN_SESSION_NAME,
                               self.mock_current_partial_token),
-                             self.mock_sesstion_set.call_args[0])
+                             self.mock_session_set.call_args[0])
 
     def test_not_to_save_to_session_when_the_response_is_a_dict(self):
         # GIVEN
@@ -114,4 +114,4 @@ def decorated_func(*args, **kwargs):
         # THEN
         self.assertEqual(expected_response, response)
         self.assertEqual(0, self.mock_partial_store.call_count)
-        self.assertEqual(0, self.mock_sesstion_set.call_count)
+        self.assertEqual(0, self.mock_session_set.call_count)
diff --git a/social_core/tests/test_utils.py b/social_core/tests/test_utils.py
index 19543f19..a54b296d 100644
--- a/social_core/tests/test_utils.py
+++ b/social_core/tests/test_utils.py
@@ -45,7 +45,7 @@ def test_valid_relative_redirect(self):
     def test_multiple_hosts(self):
         allowed_hosts = ['myapp1.com', 'myapp2.com']
         for host in allowed_hosts:
-            url = 'http://{}/path/'.format(host)
+            url = f'http://{host}/path/'
             self.assertEqual(sanitize_redirect(allowed_hosts, url), url)
 
     def test_multiple_hosts_wrong_host(self):
diff --git a/social_core/utils.py b/social_core/utils.py
index 2e2523c3..1970ef7f 100644
--- a/social_core/utils.py
+++ b/social_core/utils.py
@@ -265,7 +265,7 @@ def append_slash(url):
     'http://www.example.com/api/user/1/'
     """
     if url and not url.endswith('/'):
-        url = '{0}/'.format(url)
+        url = f'{url}/'
     return url
 
 
@@ -305,4 +305,9 @@ def wrapped(this):
                     if not cached_value:
                         raise
             return cached_value
+
+        wrapped.invalidate = self._invalidate
         return wrapped
+
+    def _invalidate(self):
+        self.cache.clear()