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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?
except ValueError:
            assert False, 'SNS response MessageId not a valid UUID'
        try:
            dateutil.parser.parse(result.pop('Timestamp'))
        except KeyError:
            assert False, 'Timestamp missing in SNS response message body'
        except ValueError:
            assert False, 'SNS response Timestamp not a valid ISO 8601 date'
        self.assertEqual(result, {
            'Message': 'msg',
            'Signature': 'EXAMPLEpH+..',
            'SignatureVersion': '1',
            'SigningCertURL':
                'https://sns.us-east-1.amazonaws.com/SimpleNotificationService-0000000000000000000000.pem',
            'SubscribeURL': None,
            'Token': None,
            'TopicArn': 'arn',
            'Type': 'Notification'
        })
        
        action = {
            'Message': ['msg'],
            'Subject': ['subject'],
            'MessageAttributes.entry.1.Name': ['attr1'],
            'MessageAttributes.entry.1.Value.DataType': ['String'],
            'MessageAttributes.entry.1.Value.StringValue': ['value1'],
            'MessageAttributes.entry.1.Value.BinaryValue': ['value1'],
            'MessageAttributes.entry.2.Name': ['attr2'],
            'MessageAttributes.entry.2.Value.DataType': ['String'],
            'MessageAttributes.entry.2.Value.StringValue': ['value2'],