pylint 2.9 thinks that __add_principal is a class-level method that is
unused. It is a local function inside one of class methods and is used
directly inside that method.
Signed-off-by: Alexander Bokovoy <abokovoy@redhat.com>
Reviewed-By: Florence Blanc-Renaud <flo@redhat.com>
Reviewed-By: Florence Blanc-Renaud <flo@redhat.com>