code: def forward(self, device_port, local_port=None):
          
          port = self._adb_device.forward(device_port, local_port)
          return (self._host, port)
docs: Forward device port to local
          Args:
              device_port: port inside device
              local_port: port on PC, if this value is None, a port will random pick one.
  
          Returns:
              tuple, (host, local_port)