code: def isinstance(self, class_or_string):
          
          if class_or_string is None:
              return False
          import inspect
          if inspect.isclass(class_or_string):
              return isinstance(self, class_or_string)
          else:
              return self.__class__.__name__.lower() == class_or_string.lower()
docs: Check whether the node is a instance of `class_or_string`.
          Unlinke the standard isinstance builtin, the method accepts either a class or a string.
          In the later case, the string is compared with self.__class__.__name__ (case insensitive).