code: def get_volumes_for_vtree(self, vtreeObj):
          
          self.conn.connection._check_login()
          all_volumes = []
          response = self._do_get("{}/{}{}/{}".format(self.conn.connection._api_url, 'instances/VTree::', vtreeObj.id, 'relationships/Volume')).json()
          for vtree_volume in response:
              all_volumes.append(
                  Volume.from_dict(vtree_volume)
              )
          return all_volumes
docs: :param vtreeObj: VTree object
              Protection Domain Object
          :return: list of Volumes attached to VTree
          :rtype: ScaleIO Volume object