Short description of error
The VertexGroup.remove method says it expects index, with the description "Remove a vertex from the group". In actuality, though, it expects a sequence and will throw an error if an index is passed.
I believe the more consistent behavior with the rest of the Python API would be for this function to expect a single integer, but I would also be happy with the documentation updating to reflect its current behavior (though if this were to be the case, I think the method would need a new name).
Exact steps for others to reproduce the error
- Open the default blend file
- With the cube selected & active, add a new vertex group
- In edit mode, assign all of the Cube vertices to the new vertex group.
- In the Python console, type the following: C.object.vertex_groups.remove(0)