class_docstr: Unbounded-for-each placeholder for supporting parallel (multi-node) steps.
code: def __getitem__(self, item):
      return item or 0
  
imports: import inspect
  import os
  import sys
  import traceback
  from itertools import islice
  from types import FunctionType, MethodType
  from typing import Any, Callable, List, Optional, Tuple
  from .None import cmd_with_io
  from .parameters import DelayedEvaluationParameter, Parameter
  from .exception import MetaflowException, MissingInMergeArtifactsException, UnhandledInMergeArtifactsException
  from .graph import FlowGraph
  from .unbounded_foreach import UnboundedForeachInput
  from .datastore.inputs import Inputs
label_desc: Use image node_id 2 for calling the ParallelUBF obj's underlying member method code with example usage: obj.__getitem__(item) and returns: unknown