:param vtreeObj: VTree object
            Protection Domain Object
        :return: list of Volumes attached to VTree
        :rtype: ScaleIO Volume object

def get_volumes_for_vtree(self, vtreeObj):
        """
        :param vtreeObj: VTree object
            Protection Domain Object
        :return: list of Volumes attached to VTree
        :rtype: ScaleIO Volume object
        """
        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