code: def test_join_multi_levels_merge_equivalence(
      self, portfolio, household, expected
  ):
      portfolio = portfolio.copy()
      household = household.copy()
  
      # equivalency
      result = merge(
          household.reset_index(),
          portfolio.reset_index(),
          on=["household_id"],
          how="inner",
      ).set_index(["household_id", "asset_id"])
      tm.assert_frame_equal(result, expected)
  
imports: import numpy
  import pytest
  import pandas.util._test_decorators
  import pandas
  from pandas import DataFrame, Index, MultiIndex, RangeIndex, Series, Timestamp, option_context
  import pandas._testing
  from pandas.core.reshape.concat import concat
  from pandas.core.reshape.merge import merge
label_desc: Use image node_id 17 for calling the TestMergeMulti obj's underlying member method code with example usage: obj.test_join_multi_levels_merge_equivalence(portfolio, household, expected) without return types