diff --git a/sdks/python/apache_beam/examples/snippets/transforms/aggregation/groupby_test.py b/sdks/python/apache_beam/examples/snippets/transforms/aggregation/groupby_test.py
index 0d2e5dfe25ad..cc3fd5c3ccd1 100644
--- a/sdks/python/apache_beam/examples/snippets/transforms/aggregation/groupby_test.py
+++ b/sdks/python/apache_beam/examples/snippets/transforms/aggregation/groupby_test.py
@@ -39,7 +39,6 @@
 from .groupby_two_exprs import groupby_two_exprs
 
 
-
 class UnorderedList(object):
   def __init__(self, contents):
     self._contents = list(contents)
diff --git a/sdks/python/apache_beam/runners/worker/operations.py b/sdks/python/apache_beam/runners/worker/operations.py
index d0f7cceb558f..f96eb3728717 100644
--- a/sdks/python/apache_beam/runners/worker/operations.py
+++ b/sdks/python/apache_beam/runners/worker/operations.py
@@ -1234,6 +1234,11 @@ def flush(self, target):
 
 
 class PGBKCVOperation(Operation):
+  """Partial group-by-key operation.
+
+  This operation handles grouped values with
+a combine function applied.
+  """
   def __init__(
       self, name_context, spec, counter_factory, state_sampler, windowing=None):
     super(PGBKCVOperation,