Currently one test is failing for the scheduler. The issue is Py3.7 changed the _worker_queue to be a SimpleQueue.

Traceback (most recent call last):
File "/Users/crwilcox/workspace/google-cloud-python/pubsub/tests/unit/pubsub_v1/subscriber/test_scheduler.py", line 51, in test_schedule
scheduler_.shutdown()
File "/Users/crwilcox/workspace/google-cloud-python/pubsub/google/cloud/pubsub_v1/subscriber/scheduler.py", line 121, in shutdown
self._executor._work_queue.
AttributeError: '_queue.SimpleQueue' object has no attribute 'queue'