<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def add_port_to_free_pool(self, port):
 """Add a new port to the free pool for allocation."""

        if port < 1 or port > 65535:
            raise ValueError(
                'Port must be in the [1, 65535] range, not %d.' % port)
        port_info = _PortInfo(port=port)
        self._port_queue.append(port_info)