code: def household(self):
      household = DataFrame(
          {
              "household_id": [1, 2, 3],
              "male": [0, 1, 0],
              "wealth": [196087.3, 316478.7, 294750],
          },
          columns=["household_id", "male", "wealth"],
      ).set_index("household_id")
      return household
  
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 13 for calling the TestMergeMulti obj's underlying member method code with example usage: obj.household() and returns: household