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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?
for topic_arn in SNS_SUBSCRIPTIONS:
        SNS_SUBSCRIPTIONS[topic_arn] = [
            sub for sub in SNS_SUBSCRIPTIONS[topic_arn]
            if sub['SubscriptionArn'] != subscription_arn
        ]
def _get_tags(topic_arn):
    if topic_arn not in SNS_TAGS:
        SNS_TAGS[topic_arn] = []
    return SNS_TAGS[topic_arn]
def do_list_tags_for_resource(topic_arn):
    return _get_tags(topic_arn)
def do_tag_resource(topic_arn, tags):
    existing_tags = SNS_TAGS.get(topic_arn, [])
    tags = [
        tag for idx, tag in enumerate(tags)
        if tag not in tags[:idx]
    ]
    def existing_tag_index(item):
        for idx, tag in enumerate(existing_tags):
            if item['Key'] == tag['Key']:
                return idx
        return None
    for item in tags:
        existing_index = existing_tag_index(item)
        if existing_index is None:
            existing_tags.append(item)
        else:
            existing_tags[existing_index] = item
    SNS_TAGS[topic_arn] = existing_tags
def do_untag_resource(topic_arn, tag_keys):