Deletes this Ethernet switch.

def close(self):
        """
        Deletes this Ethernet switch.
        """
        yield from self._telnet.close()
        self._telnet_server.close()
        
        for nio in self._nios.values():
            if nio:
                yield from nio.close()
        self.manager.port_manager.release_tcp_port(self._console, self._project)
        if self._hypervisor:
            try:
                yield from self._hypervisor.send('ethsw delete "{}"'.format(self._name))
                log.info('Ethernet switch "{name}" [{id}] has been deleted'.format(name=self._name, id=self._id))
            except DynamipsError:
                log.debug("Could not properly delete Ethernet switch {}".format(self._name))
        if self._hypervisor and self in self._hypervisor.devices:
            self._hypervisor.devices.remove(self)
        if self._hypervisor and not self._hypervisor.devices:
            yield from self.hypervisor.stop()
            self._hypervisor = None
        return True