call server procedure

def call(self, proc_name, field_types, *args):
        """
        call server procedure
        """
        d = self.replyQueue.get()
        packet = RequestCall(self.charset, self.errors, d._ipro_request_id, proc_name, 0, *args)
        self.transport.write(bytes(packet))
        return d.addCallback(self.handle_reply, self.charset, self.errors, field_types)