code: def test_alignment(self):
      x = Series(
          data=[1, 2, 3],
          index=MultiIndex.from_tuples([("A", 1), ("A", 2), ("B", 3)]),
      )
  
      y = Series(
          data=[4, 5, 6],
          index=MultiIndex.from_tuples([("Z", 1), ("Z", 2), ("B", 3)]),
      )
  
      res = x - y
      exp_index = x.index.union(y.index)
      exp = x.reindex(exp_index) - y.reindex(exp_index)
      tm.assert_series_equal(res, exp)
  
      # hit non-monotonic code path
      res = x[::-1] - y[::-1]
      exp_index = x.index.union(y.index)
      exp = x.reindex(exp_index) - y.reindex(exp_index)
      tm.assert_series_equal(res, exp)
  
imports: import datetime
  import numpy
  import pytest
  import pandas
  from pandas import DataFrame, MultiIndex, Series
  import pandas._testing
label_desc: Use image node_id 8 for calling the TestMultiLevel obj's underlying member method code with example usage: obj.test_alignment() without return types