<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def disconnect_network_gateway(self, gateway_id, body=None):
 """Disconnect a network from the specified gateway."""

        base_uri = self.network_gateway_path % gateway_id
        return self.put("%s/disconnect_network" % base_uri, body=body)