def METHOD_NAME(self, meta_data, request_pdu):
    """ Execute configured route based on requests meta data and request
    PDU.
    :param meta_data: A dict with meta data. It must at least contain
        key 'unit_id'.
    :param request_pdu: A bytearray containing request PDU.
    :return: A bytearry containing reponse PDU.
    """
    try:
        function = create_function_from_request_pdu(request_pdu)
        results =\
            function.execute(meta_data['unit_id'], self.server.route_map)
        try:
            # ReadFunction's use results of callbacks to build response
            # PDU...
            return function.create_response_pdu(results)
        except TypeError:
            # ...other functions don't.
            return function.create_response_pdu()
    except ModbusError as e:
        function_code = get_function_code_from_request_pdu(request_pdu)
        return pack_exception_pdu(function_code, e.error_code)
    except Exception:
        log.exception('Could not handle request')
        function_code = get_function_code_from_request_pdu(request_pdu)
        return pack_exception_pdu(function_code,
                                  ServerDeviceFailureError.error_code)