class_docstr: Stateful operator
class_docstr_tok: ["Stateful","operator"]
code: def __call__(self, num: int):
      return self._factor + num
  
imports: from towhee.operator import PyOperator, SharedType
label_desc: Use image node_id 2 for calling the OldAdd obj's underlying member method code with example usage: obj.__call__(num) and returns: unknown