code: def test_sort_index_na_position(self):
      # GH#51612
      df = DataFrame(
          [1, 2], index=MultiIndex.from_tuples([(1, 1), (1, pd.NA)])
      )
      expected = df.copy()
      result = df.sort_index(level=[0, 1], na_position="last")
      tm.assert_frame_equal(result, expected)
  
imports: import numpy
  import pytest
  import pandas
  from pandas import CategoricalDtype, CategoricalIndex, DataFrame, IntervalIndex, MultiIndex, RangeIndex, Series, Timestamp
  import pandas._testing
label_desc: Use image node_id 7 for calling the TestDataFrameSortIndexKey obj's underlying member method code with example usage: obj.test_sort_index_na_position() without return types