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Under utils/common.py, 

TIMESTAMP_FORMAT_MILLIS = '%Y-%m-%dT%H:%M:%S.%fZ'

The %f produces time with microseconds, for example: 2020-03-18T19:43:18.115783Z.


However, when interacting the AWS s3 and sns apis, I receive DateTimes like this:

2020-03-02T22:32:13.240Z
i.e. milliseconds. 

This seems like a simple change to the utils. TIMESTAMP_FORMAT_MILLIS is named as if it should be millis as well. This is seems like a simple change. Is there a reason it should be microseconds?
def setUp(self):
        self.subscriber = {
            'Protocol': 'sqs',
            'RawMessageDelivery': 'false',
            'TopicArn': 'arn',
        }
        
        sns_listener.SNS_SUBSCRIPTIONS = {}
    def test_unsubscribe_without_arn_should_error(self):
        sns = sns_listener.ProxyListenerSNS()
        error = sns.forward_request('POST', '/', 'Action=Unsubscribe', '')
        self.assertTrue(error is not None)
        self.assertEqual(error.status_code, 400)
    def test_unsubscribe_should_remove_listener(self):
        sub_arn = 'arn:aws:sns:us-east-1:123456789012:test-topic:45e61c7f-dca5-4fcd-be2b-4e1b0d6eef72'
        topic_arn = 'arn:aws:sns:us-east-1:123456789012:test-topic'
        self.assertFalse(sns_listener.get_topic_by_arn(topic_arn))
        sns_listener.do_create_topic(topic_arn)
        self.assertTrue(sns_listener.get_topic_by_arn(topic_arn) is not None)
        sns_listener.do_subscribe(
            topic_arn,
            'arn:aws:sqs:us-east-1:123456789012:test-queue',
            'sqs',
            sub_arn,
            {}
        )
        self.assertTrue(sns_listener.get_subscription_by_arn(sub_arn))
        sns_listener.do_unsubscribe(sub_arn)
        self.assertFalse(sns_listener.get_subscription_by_arn(sub_arn))
    def test_get_subscribe_attributes(self):