code: def test_is_datetime_series():
      assert not dataframe_utils.is_datetime_series(None)
      assert not dataframe_utils.is_datetime_series(
          pd.DataFrame({"foo": [1]})
      )
      assert not dataframe_utils.is_datetime_series(
          pd.Series([1, 2, 3])
      )
      assert not dataframe_utils.is_datetime_series(
          pd.Series(["1", "2", "3"])
      )
      assert not dataframe_utils.is_datetime_series(pd.Series())
      assert not dataframe_utils.is_datetime_series(
          pd.Series([None, None])
      )
      assert dataframe_utils.is_datetime_series(
          pd.Series(
              [
                  datetime.date(2018, 1, 1),
                  datetime.date(2018, 1, 2),
                  None,
              ]
          )
      )
      assert dataframe_utils.is_datetime_series(
          pd.Series(
              [datetime.date(2018, 1, 1), datetime.date(2018, 1, 2)]
          )
      )
      assert dataframe_utils.is_datetime_series(
          pd.Series(
              [
                  datetime.datetime(2018, 1, 1),
                  datetime.datetime(2018, 1, 2),
                  None,
              ]
          )
      )
      assert dataframe_utils.is_datetime_series(
          pd.Series(
              [
                  datetime.datetime(2018, 1, 1),
                  datetime.datetime(2018, 1, 2),
              ]
          )
      )
      assert dataframe_utils.is_datetime_series(
          pd.date_range(
              datetime.date(2018, 1, 1), datetime.date(2018, 2, 1)
          ).to_series()
      )
      assert dataframe_utils.is_datetime_series(
          pd.date_range(
              datetime.datetime(2018, 1, 1),
              datetime.datetime(2018, 2, 1),
          ).to_series()
      )
  
imports: import datetime
  import pandas
  from superset.common.utils import dataframe_utils
label_desc: Use image node_id 1 for calling a global function with example usage: test_is_datetime_series() without return types