I think Version 13 and up support tags.
from netapp_ontap import HostConnection
from netapp_ontap.resources import Volume
with HostConnection("<mgmt-ip>", username="admin", password="password", verify=False):
resource = Volume(uuid="d0c3359c-5448-4a9b-a077-e3295a7e9057")
resource.tiering.object_tags = ["key1=val1", "key2=val2"]
resource.patch()