code: def test_nat_arithmetic_index(op_name, value):
      # see gh-11718
      exp_name = "x"
      exp_data = [NaT] * 2
  
      if value.dtype.kind == "M" and "plus" in op_name:
          expected = DatetimeIndex(exp_data, tz=value.tz, name=exp_name)
      else:
          expected = TimedeltaIndex(exp_data, name=exp_name)
      expected = expected.as_unit(value.unit)
  
      if not isinstance(value, Index):
          expected = expected.array
  
      op = _ops[op_name]
      result = op(NaT, value)
      tm.assert_equal(result, expected)
  
imports: from datetime import datetime, timedelta
  import operator
  import numpy
  import pytest
  import pytz
  from pandas._libs.tslibs import iNaT
  from pandas.compat.numpy import np_version_gte1p24p3
  from pandas import DatetimeIndex, DatetimeTZDtype, Index, NaT, Period, Series, Timedelta, TimedeltaIndex, Timestamp, isna, offsets
  import pandas._testing
  from pandas.core import roperator
  from pandas.core.arrays import DatetimeArray, PeriodArray, TimedeltaArray
label_desc: Use image node_id 15 for calling a global function with example usage: test_nat_arithmetic_index(op_name, value) without return types