class_docstr: Flat input list.
code: def output_schema(self):
      return [(int, (1,)), (int, (1,))]
  
file_path: towhee/tests/unittests/mock_operators/sum_operator/sum_operator.py
imports: from typing import NamedTuple, List
  from towhee.operator import Operator, SharedType
label_desc: Use image node_id 5 for calling the SumOperator obj's underlying member method code with example usage: obj.output_schema() and returns: list