def METHOD_NAME(self, service_response_mock):
    service_response_mock.return_value = "InvalidRequestContent"
    response = LambdaErrorResponses.invalid_request_content("InvalidRequestContent")
    self.assertEqual(response, "InvalidRequestContent")
    service_response_mock.assert_called_once_with(
        '{"Type": "User", "Message": "InvalidRequestContent"}',
        {"x-amzn-errortype": "InvalidRequestContent", "Content-Type": "application/json"},
        400,
    )