fix: Typecheck errors in samples/snippets/subscriber.py (#1186)

Co-authored-by: Owl Bot <gcf-owl-bot[bot]@users.noreply.github.com>
Co-authored-by: Anthonios Partheniou <partheniou@google.com>

samples/snippets/mypy.ini

@@ -4,5 +4,9 @@ strict = True
 exclude = noxfile\.py
 warn_unused_configs = True
 
-[mypy-avro.*,backoff,flaky]
+; Ignore errors caused due to missing library stubs or py.typed marker
+; Refer https://mypy.readthedocs.io/en/stable/running_mypy.html#missing-library-stubs-or-py-typed-marker
+; Errors ignored instead of adding stubs as a workaround, since this directory contains sample code
+; that does not affect the functionality of the client library.
+[mypy-avro.*,backoff,flaky,google.cloud.*]
 ignore_missing_imports = True

samples/snippets/subscriber.py

@@ -528,8 +528,10 @@ def update_subscription_with_dead_letter_policy(
     )
 
     with subscriber:
-        subscription_after_update = subscriber.update_subscription(
-            request={"subscription": subscription, "update_mask": update_mask}
+        subscription_after_update: gapic_types.Subscription = (
+            subscriber.update_subscription(
+                request={"subscription": subscription, "update_mask": update_mask}
+            )
         )
 
     print(f"After the update: {subscription_after_update}.")
@@ -573,8 +575,10 @@ def remove_dead_letter_policy(
     )
 
     with subscriber:
-        subscription_after_update = subscriber.update_subscription(
-            request={"subscription": subscription, "update_mask": update_mask}
+        subscription_after_update: gapic_types.Subscription = (
+            subscriber.update_subscription(
+                request={"subscription": subscription, "update_mask": update_mask}
+            )
         )
 
     print(f"After removing the policy: {subscription_after_update}.")