I just tried the fixup script and ran into a few issues.

1. It generates this change even though PublisherClient.publish does not take the new style parameters:

-        publisher_client.publish(topic, bytes(json.dumps(message), 'utf-8'))
+        publisher_client.publish(request = {'topic': topic, 'messages': bytes(json.dumps(message), 'utf-8')})

2. It generates this change even though request and keyword args are documented to be mutually exclusive:

-        response = subscriber.pull(subscription_path, max_messages=NUM_MESSAGES, timeout=TIMEOUT)
+        response = subscriber.pull(
+            request = {'subscription': subscription_path, 'max_messages': NUM_MESSAGES}, timeout=TIMEOUT,
+        )

3. all of the generated request keyword arguments break pep8 (they should not have spaces around =)

Stylistically, I find the keyword arguments better to read than all of the inline dicts for the request syntax. It'd be great if the tool had an option to emit the keyword args version.