hi @pj812!
This error means that you are passing the wrong client.
right now, python v4 client package will include both v3 and v4 code.
the difference is how you instantiate the client.
for v3:
client = weaviate.Client("http://localhost:8080")
while for v4:
client = weaviate.connect_to_local()
connect_to_local or other option.
Check here for a nice doc on how to migrate:
Thanks!