Another batch of type annotations

mypy.ini

@@ -146,6 +146,9 @@ disallow_untyped_defs = True
 [mypy-synapse.logging.context]
 disallow_untyped_defs = True
 
+[mypy-synapse.logging.formatter]
+disallow_untyped_defs = True
+
 [mypy-synapse.logging.handlers]
 disallow_untyped_defs = True
 

synapse/logging/formatter.py

@@ -16,6 +16,8 @@
 import logging
 import traceback
 from io import StringIO
+from types import TracebackType
+from typing import Tuple, Optional, Type
 
 
 class LogFormatter(logging.Formatter):
@@ -28,10 +30,14 @@ class LogFormatter(logging.Formatter):
     where it was caught are logged).
     """
 
-    def __init__(self, *args, **kwargs):
-        super().__init__(*args, **kwargs)
-
-    def formatException(self, ei):
+    def formatException(
+        self,
+        ei: Tuple[
+            Optional[Type[BaseException]],
+            Optional[BaseException],
+            Optional[TracebackType],
+        ],
+    ) -> str:
         sio = StringIO()
         (typ, val, tb) = ei