code: def _index_level_name(index, i, column_names):
      """Return the name of an index level or a default name if `index.name` is
      None or is already a column name.
  
      Parameters
      ----------
      index : pandas.Index
      i : int
  
      Returns
      -------
      name : str
      """
      if index.name is not None and index.name not in column_names:
          return _column_name_to_strings(index.name)
      else:
          return "__index_level_{:d}__".format(i)
  
imports: import ast
  from collections.abc import Sequence
  from concurrent import futures
  import concurrent.futures.thread
  from copy import deepcopy
  from itertools import zip_longest
  import json
  import operator
  import re
  import warnings
  import numpy
  import pyarrow
  from pyarrow.lib import _pandas_api, frombytes
label_desc: Use image node_id 9 for calling a global function with example usage: _index_level_name(index, i, column_names) and returns: _column_name_to_strings, str