code: def test_sort_index_multiindex(self, level):
      mi = MultiIndex.from_tuples(
          [[1, 1, 3], [1, 1, 1]], names=list("ABC")
      )
      s = Series([1, 2], mi)
      backwards = s.iloc[[1, 0]]
  
      # implicit sort_remaining=True
      res = s.sort_index(level=level)
      tm.assert_series_equal(backwards, res)
  
      # GH#13496
      # sort has no effect without remaining lvls
      res = s.sort_index(level=level, sort_remaining=False)
      tm.assert_series_equal(s, res)
  
imports: import numpy
  import pytest
  from pandas import DatetimeIndex, IntervalIndex, MultiIndex, Series
  import pandas._testing
label_desc: Use image node_id 5 for calling the TestSeriesSortIndex obj's underlying member method code with example usage: obj.test_sort_index_multiindex(level) without return types