diff --git a/sdks/python/apache_beam/transforms/periodicsequence.py b/sdks/python/apache_beam/transforms/periodicsequence.py
index 56075a5acc71..6127aa8de555 100644
--- a/sdks/python/apache_beam/transforms/periodicsequence.py
+++ b/sdks/python/apache_beam/transforms/periodicsequence.py
@@ -50,6 +50,10 @@ def create_tracker(self, restriction):
   def restriction_size(self, unused_element, restriction):
     return restriction.size()
 
+  # On drain, immediately stop emitting new elements
+  def truncate(self, unused_element, unused_restriction):
+    return None
+
 
 class ImpulseSeqGenDoFn(beam.DoFn):
   '''