code: def test_leaf(self, es):
      es.add_last_time_indexes()
      log = es["log"]
      lti_name = log.ww.metadata.get("last_time_index")
  
      assert lti_name == LTI_COLUMN_NAME
      assert len(log[lti_name]) == 17
  
      log_df = to_pandas(log)
  
      for v1, v2 in zip(log_df[lti_name], log_df["datetime"]):
          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 1 for calling the TestLastTimeIndex obj's underlying member method code with example usage: obj.test_leaf(es) without return types