code: def add_internal_subnet(self, context_id, subnet_id):
          
          return self.context.addPrivateSubnetToNetworkTunnel(subnet_id,
                                                              id=context_id)
docs: Add an internal subnet to a tunnel context.
  
          :param int context_id: The id-value representing the context instance.
          :param int subnet_id: The id-value representing the internal subnet.
          :return bool: True if internal subnet addition was successful.