revoke_roles documentation wrong

Documentation says:

Arguments username and user are mutually exclusive. You can either set one or the other, but not both.
if username and user are not given, the authenticated member will be used.
https://docs.plone.org/develop/plone.api/docs/api/user.html#plone.api.user.revoke_roles

But if I omit the user and username like so: api.user.revoke_roles(obj=item, roles=["Owner"])

I got an

...
  Module kup.tfv.db.gfk.einzel, line 161, in action_add
  Module <decorator-gen-41>, line 2, in revoke_roles
  Module plone.api.validation, line 81, in wrapped
  Module <decorator-gen-40>, line 2, in revoke_roles
  Module plone.api.validation, line 116, in wrapped
  Module plone.api.user, line 414, in revoke_roles
  Module <decorator-gen-31>, line 2, in get
  Module plone.api.validation, line 116, in wrapped
  Module <decorator-gen-30>, line 2, in get
  Module plone.api.validation, line 146, in wrapped
plone.api.exc.MissingParameterError: At least one of these parameters must be supplied: userid, username.

Now, question is - is the documentation wrong or is it the implemenation?

Compare the revoke_roles documentation at the linked user API page with the behavior of the plone.api.user revoke_roles entry point and its parameter validation. Confirm whether omitted user and username should use the authenticated member, then update the documentation or report the implementation discrepancy so the documented behavior and actual result agree.