code: def _join_dirname(self, *args):
          
          # extra function because I need to use it in a method that defines
          # the kwarg 'os', which collides with os.path...
          return os.path.join(os.path.dirname(args[0]), *args[1:])
docs: return os.path.join(os.path.dirname(args[0]), *args[1:])