def METHOD_NAME(self):
    self.set_http_response(status_code=200)
    taggedEC2Object = TaggedEC2Object(self.service_connection)
    taggedEC2Object.id = "i-abcd1234"
    taggedEC2Object.tags["already_present_key"] = "already_present_value"
    taggedEC2Object.add_tag("new_key", "new_value")
    self.assert_request_parameters({
        'ResourceId.1': 'i-abcd1234',
        'Action': 'CreateTags',
        'Tag.1.Key': 'new_key',
        'Tag.1.Value': 'new_value'},
        ignore_params_values=['AWSAccessKeyId', 'SignatureMethod',
                              'SignatureVersion', 'Timestamp',
                              'Version'])
    self.assertEqual(taggedEC2Object.tags, {
        "already_present_key": "already_present_value",
        "new_key": "new_value"})