code: def drop_port(self, port, interface=None, subnet=None):
          
          args = {
              'port': port,
              'interface': interface,
              'subnet': subnet,
          }
          self._port_chk.check(args)
  
          return self._client.json('nft.drop_port', args)
docs: close an opened port (takes the same parameters passed in open)
          :param port: then port number
          :param interface: an optional interface to close the port for
          :param subnet: an optional subnet to close the port for