Removes an adapter NIO binding.

        :param adapter_number: adapter number
        :param port_number: port number
        :returns: NIO instance

def adapter_remove_nio_binding(self, adapter_number, port_number):
        """
        Removes an adapter NIO binding.

        :param adapter_number: adapter number
        :param port_number: port number
        :returns: NIO instance
        """

        try:
            adapter = self._adapters[adapter_number]
        except IndexError:
            raise IOUError('Adapter {adapter_number} does not exist on IOU "{name}"'.format(name=self._name,
                                                                                            adapter_number=adapter_number))

        if not adapter.port_exists(port_number):
            raise IOUError("Port {port_number} does not exist in adapter {adapter}".format(adapter=adapter,
                                                                                           port_number=port_number))

        nio = adapter.get_nio(port_number)
        if isinstance(nio, NIOUDP):
            self.manager.port_manager.release_udp_port(nio.lport, self._project)
        adapter.remove_nio(port_number)
        log.info('IOU "{name}" [{id}]: {nio} removed from {adapter_number}/{port_number}'.format(name=self._name,
                                                                                                 id=self._id,
                                                                                                 nio=nio,
                                                                                                 adapter_number=adapter_number,
                                                                                                 port_number=port_number))

        if self.ubridge:
            bridge_name = "IOL-BRIDGE-{}".format(self.application_id + 512)
            yield from self._ubridge_send("iol_bridge delete_nio_udp {name} {bay} {unit}".format(name=bridge_name,
                                                                                                 bay=adapter_number,
                                                                                                 unit=port_number))

        return nio