docs: def _next_in_mro(cls):
      """Helper for Generic.__new__.
  
      Returns the class after the last occurrence of Generic or
      Generic[...] in cls.__mro__.
      """
      next_in_mro = object
      # Look for the last occurrence of Generic or Generic[...].
      for i, c in enumerate(cls.__mro__[:-1]):
          if isinstance(c, GenericMeta) and _gorg(c) is Generic:
              next_in_mro = cls.__mro__[i + 1]
      return next_in_mro