code: def test_dates(self, mock_handler):
      df = pd.DataFrame(
          [
              {"a": 1, "b": dt.datetime(2020, 1, 1)},
              {"a": 2, "b": dt.datetime(2020, 1, 2)},
              {"a": 1, "b": dt.datetime(2020, 1, 3)},
          ]
      )
      self.set_handler(mock_handler, name="pg", tables={"tasks": df})
  
      # --- use predictor ---
      predictor = {
          "name": "task_model",
          "predict": "p",
          "dtypes": {
              "p": dtype.float,
              "a": dtype.integer,
              "b": dtype.categorical,
          },
          "predicted_value": 3.14,
      }
      self.set_predictor(predictor)
  
      ret = self.execute(
          """
              SELECT a, last(b)
              FROM (
                 SELECT res.a, res.b
                 FROM pg.tasks as source
                 JOIN mindsdb.task_model as res
              )
              group by 1
              order by a
          """
      )
      assert len(ret.data) == 2
      # is last datetime value of a = 1
      assert (
          ret.data[0][1].isoformat()
          == dt.datetime(2020, 1, 3).isoformat()
      )
  
imports: from unittest.mock import patch
  import datetime
  import tempfile
  import pytest
  import pandas
  import numpy
  from mindsdb_sql.render.sqlalchemy_render import SqlalchemyRender
  from mindsdb.api.executor.utilities.sql import query_df
  from mindsdb.api.mysql.mysql_proxy.utilities.lightwood_dtype import dtype
  from .executor_test_base import BaseExecutorMockPredictor
label_desc: Use image node_id 5 for calling the Test obj's underlying member method code with example usage: obj.test_dates(mock_handler) without return types