def create_from_request_pdu(pdu):

        """ Create instance from request PDU.
        :param pdu: A request PDU.
        :return: Instance of this class.
        """
        _, starting_address, quantity = struct.unpack('>BHH', pdu)

        instance = ReadHoldingRegisters()
        instance.starting_address = starting_address
        instance.quantity = quantity

        return instance
Create instance from request PDU.
        :param pdu: A request PDU.
        :return: Instance of this class.