diff --git a/apache_beam/runners/worker/operations.py b/apache_beam/runners/worker/operations.py
index 3464c5750c..5921c72b90 100644
--- a/apache_beam/runners/worker/operations.py
+++ b/apache_beam/runners/worker/operations.py
@@ -69,18 +69,6 @@ if TYPE_CHECKING:
   from apache_beam.runners.worker.statesampler import StateSampler
   from apache_beam.transforms.userstate import TimerSpec
 
-# Allow some "pure mode" declarations.
-try:
-  import cython
-except ImportError:
-
-  class FakeCython(object):
-    @staticmethod
-    def cast(type, value):
-      return value
-
-  globals()['cython'] = FakeCython()
-
 _globally_windowed_value = GlobalWindows.windowed_value(None)
 _global_window_type = type(_globally_windowed_value.windows[0])
 
@@ -149,7 +137,7 @@ class ConsumerSet(Receiver):
     # type: (WindowedValue) -> None
     self.update_counters_start(windowed_value)
     for consumer in self.consumers:
-      cython.cast(Operation, consumer).process(windowed_value)
+      consumer.process(windowed_value)
     self.update_counters_finish()
 
   def try_split(self, fraction_of_remainder):
@@ -345,7 +333,7 @@ class Operation(object):
 
   def output(self, windowed_value, output_index=0):
     # type: (WindowedValue, int) -> None
-    cython.cast(Receiver, self.receivers[output_index]).receive(windowed_value)
+    self.receivers[output_index].receive(windowed_value)
 
   def add_receiver(self, operation, output_index=0):
     # type: (Operation, int) -> None