class_docstr: Data source op
class_docstr_tok: ["Data","source","op"]
code: def __call__(self):
      for data in self._data:
          yield 0, data
  
imports: from towhee.operator import PyOperator, SharedType
label_desc: Use image node_id 2 for calling the Ds obj's underlying member method code with example usage: obj.__call__() without return types