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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?
if 'sqs_queue_url' in subscriber:
                    queue_url = subscriber.get('sqs_queue_url')
                elif '://' in endpoint:
                    queue_url = endpoint
                else:
                    queue_name = endpoint.split(':')[5]
                    queue_url = aws_stack.get_sqs_queue_url(queue_name)
                    subscriber['sqs_queue_url'] = queue_url
                sqs_client.send_message(
                    QueueUrl=queue_url,
                    MessageBody=create_sns_message_body(subscriber, req_data),
                    MessageAttributes=create_sqs_message_attributes(subscriber, message_attributes)
                )
            except Exception as exc:
                sns_error_to_dead_letter_queue(subscriber['SubscriptionArn'], req_data, str(exc))
                return make_error(message=str(exc), code=400)
        elif subscriber['Protocol'] == 'lambda':
            try:
                response = lambda_api.process_sns_notification(
                    subscriber['Endpoint'],
                    topic_arn,
                    subscriber['SubscriptionArn'],
                    message,
                    message_attributes,
                    subject=req_data.get('Subject', [None])[0]
                )
                if isinstance(response, FlaskResponse):
                    response.raise_for_status()
            except Exception as exc:
                LOGGER.warning('Unable to run Lambda function on SNS message: %s %s' % (exc, traceback.format_exc()))