code: def _standardize_iterables(node):
      """Converts the given iterables to a {field: function} dictionary,
      if necessary, where the function returns a list."""
      if not node.iterables:
          return
      iterables = node.iterables
      # The candidate iterable fields
      fields = set(node.inputs.copyable_trait_names())
      # A synchronize iterables node without an itersource can be in
      # [fields, value tuples] format rather than
      # [(field, value list), (field, value list), ...]
      if node.synchronize:
          if len(iterables) == 2:
              first, last = iterables
              if all(
                  isinstance(item, (str, bytes)) and item in fields
                  for item in first
              ):
                  iterables = _transpose_iterables(first, last)
  
      # Convert a tuple to a list
      if isinstance(iterables, tuple):
          iterables = [iterables]
      # Validate the standard [(field, values)] format
      _validate_iterables(node, iterables, fields)
      # Convert a list to a dictionary
      if isinstance(iterables, list):
          # Convert a values list to a function. This is a legacy
          # Nipype requirement with unknown rationale.
          if not node.itersource:
  
              def make_field_func(*pair):
                  return pair[0], lambda: pair[1]
  
              iter_items = [
                  make_field_func(*field_value1)
                  for field_value1 in iterables
              ]
              iterables = dict(iter_items)
      node.iterables = iterables
  
imports: import os
  import sys
  import pickle
  from collections import defaultdict
  import re
  from copy import deepcopy
  from glob import glob
  from pathlib import Path
  from traceback import format_exception
  from hashlib import sha1
  from functools import reduce
  import numpy
  from ...None import logging, config
  from ...utils.filemanip import indirectory, relpath, fname_presuffix, ensure_list, get_related_files, save_json, savepkl, loadpkl, write_rst_header, write_rst_dict, write_rst_list
  from ...utils.misc import str2bool
  from ...utils.functions import create_function_from_source
  from ...interfaces.base.traits_extension import rebase_path_traits, resolve_path_traits, OutputMultiPath, isdefined, Undefined
  from ...interfaces.base.support import Bunch, InterfaceResult
  from ...interfaces.base import CommandLine
  from ...interfaces.utility import IdentityInterface
  from ...utils.provenance import ProvStore, pm, nipype_ns, get_id
  from inspect import signature
label_desc: Use image node_id 33 for calling a global function with example usage: _standardize_iterables(node) and returns: pair,  function