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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?
elif req_action == 'ListTagsForResource':
                tags = do_list_tags_for_resource(topic_arn)
                content = '<Tags/>'
                if len(tags) > 0:
                    content = '<Tags>'
                    for tag in tags:
                        content += '<member>'
                        content += '<Key>%s</Key>' % tag['Key']
                        content += '<Value>%s</Value>' % tag['Value']
                        content += '</member>'
                    content += '</Tags>'
                return make_response(req_action, content=content)
            elif req_action == 'CreateTopic':
                topic_arn = aws_stack.sns_topic_arn(req_data['Name'][0])
                self._extract_tags(topic_arn, req_data)
            elif req_action == 'TagResource':
                self._extract_tags(topic_arn, req_data)
                return make_response(req_action)
            elif req_action == 'UntagResource':
                tags_to_remove = []
                req_tags = {k: v for k, v in req_data.items() if k.startswith('TagKeys.member.')}
                req_tags = req_tags.values()
                for tag in req_tags:
                    tags_to_remove.append(tag[0])
                do_untag_resource(topic_arn, tags_to_remove)
                return make_response(req_action)
            data = self._reset_account_id(data)
            return Request(data=data, headers=headers, method=method)
        return True
    def _extract_tags(self, topic_arn, req_data):