code: def test_multiple_children(self, es, wishlist_df, true_sessions_lti):
      if es.dataframe_type == Library.SPARK:
          pytest.xfail("Cannot make index on a Spark DataFrame")
      # test all instances in both children
      if es.dataframe_type == Library.DASK:
          wishlist_df = dd.from_pandas(wishlist_df, npartitions=2)
      logical_types = {
          "session_id": Integer,
          "datetime": Datetime,
          "product_id": Categorical,
      }
      es.add_dataframe(
          dataframe_name="wishlist_log",
          dataframe=wishlist_df,
          index="id",
          make_index=True,
          time_index="datetime",
          logical_types=logical_types,
      )
      es.add_relationship(
          "sessions", "id", "wishlist_log", "session_id"
      )
      es.add_last_time_indexes()
      sessions = es["sessions"]
      # wishlist df has more recent events for two session ids
      true_sessions_lti[1] = pd.Timestamp("2011-4-9 10:31:30")
      true_sessions_lti[3] = pd.Timestamp("2011-4-10 10:41:00")
  
      lti_name = sessions.ww.metadata.get("last_time_index")
      assert len(sessions[lti_name]) == 6
      sorted_lti = to_pandas(sessions[lti_name]).sort_index()
      for v1, v2 in zip(sorted_lti, true_sessions_lti):
          assert (pd.isnull(v1) and pd.isnull(v2)) or v1 == v2
  
imports: from datetime import datetime
  import pandas
  import pytest
  from woodwork.logical_types import Categorical, Datetime, Integer
  from featuretools.entityset.entityset import LTI_COLUMN_NAME
  from featuretools.tests.testing_utils import to_pandas
  from featuretools.utils.gen_utils import Library, import_or_none
label_desc: Use image node_id 7 for calling the TestLastTimeIndex obj's underlying member method code with example usage: obj.test_multiple_children(es, wishlist_df, true_sessions_lti) without return types