def handle_error(self, exp):
        """Called if a Mapper returns MappingInvalid. Should handle the error
        and return it in the appropriate format, can be overridden in order
        to change the error format.

        :param exp: MappingInvalid exception raised
        """
        payload = {
            "message": "Invalid or incomplete data provided.",
            "errors": exp.errors
        }
        self.endpoint.return_error(self.error_status, payload=payload)
Called if a Mapper returns MappingInvalid. Should handle the error
        and return it in the appropriate format, can be overridden in order
        to change the error format.

        :param exp: MappingInvalid exception raised