code: def test_join_index_levels():
      # GH#53093
      midx = midx = MultiIndex.from_tuples(
          [("a", "2019-02-01"), ("a", "2019-02-01")]
      )
      midx2 = MultiIndex.from_tuples([("a", "2019-01-31")])
      result = midx.join(midx2, how="outer")
      expected = MultiIndex.from_tuples(
          [
              ("a", "2019-01-31"),
              ("a", "2019-02-01"),
              ("a", "2019-02-01"),
          ]
      )
      tm.assert_index_equal(result.levels[1], expected.levels[1])
      tm.assert_index_equal(result, expected)
  
file_path: pandas/pandas/tests/indexes/multi/test_join.py
imports: import numpy
  import pytest
  from pandas import DataFrame, Index, Interval, MultiIndex, Series, StringDtype
  import pandas._testing
label_desc: Use image node_id 13 for calling a global function with example usage: test_join_index_levels() without return types