diff --git a/python/google/protobuf/internal/api_implementation.py b/python/google/protobuf/internal/api_implementation.py
index 1c8462144462..e4f7687f4597 100755
--- a/python/google/protobuf/internal/api_implementation.py
+++ b/python/google/protobuf/internal/api_implementation.py
@@ -152,12 +152,6 @@ def Type():
   return _implementation_type
 
 
-def _SetType(implementation_type):
-  """Never use! Only for protobuf benchmark."""
-  global _implementation_type
-  _implementation_type = implementation_type
-
-
 # See comment on 'Type' above.
 # TODO(jieluo): Remove the API, it returns a constant. b/228102101
 def Version():