docs: def mro(self, cls):
          """
          Returns a method resolution list of documentation objects
          for `cls`, which must be a documentation object.
  
          The list will contain objects belonging to `pydoc.Class` or
          `pydoc.External`. Objects belonging to the former are exported
          classes either in this module or in one of its sub-modules.
          """
          ups = inspect.getmro(cls.cls)
          return list(map(lambda c: self.find_class(c), ups))