code: def test_get_trend_changepoint_dates_from_cols():
      # hourly changepoints
      changepoint_cols = [
          "ct1",
          "changepoint0_2020_01_05_03",
          "changepoint1_2020_02_08_00",
      ]
      changepoint_dates = get_trend_changepoint_dates_from_cols(
          changepoint_cols
      )
      expected_changepoint_dates = list(
          pd.to_datetime(["2020-01-05-03", "2020-02-08"])
      )
      assert changepoint_dates == expected_changepoint_dates
      # minute level changepoints
      changepoint_cols = [
          "ct1",
          "changepoint0_2020_01_05_03_05",
          "changepoint1_2020_02_08_00",
      ]
      changepoint_dates = get_trend_changepoint_dates_from_cols(
          changepoint_cols
      )
      expected_changepoint_dates = list(
          pd.to_datetime(["2020-01-05 03:05", "2020-02-08"])
      )
      assert changepoint_dates == expected_changepoint_dates
      # no changepoints
      changepoint_cols = ["ct1"]
      changepoint_dates = get_trend_changepoint_dates_from_cols(
          changepoint_cols
      )
      assert changepoint_dates == []
  
imports: from datetime import datetime
  import numpy
  import pandas
  import pytest
  from greykite.algo.changepoint.adalasso.changepoints_utils import adaptive_lasso_cv
  from greykite.algo.changepoint.adalasso.changepoints_utils import build_seasonality_feature_df_from_detection_result
  from greykite.algo.changepoint.adalasso.changepoints_utils import build_seasonality_feature_df_with_changes
  from greykite.algo.changepoint.adalasso.changepoints_utils import build_trend_feature_df_with_changes
  from greykite.algo.changepoint.adalasso.changepoints_utils import check_freq_unit_at_most_day
  from greykite.algo.changepoint.adalasso.changepoints_utils import combine_detected_and_custom_trend_changepoints
  from greykite.algo.changepoint.adalasso.changepoints_utils import compute_fitted_components
  from greykite.algo.changepoint.adalasso.changepoints_utils import compute_min_changepoint_index_distance
  from greykite.algo.changepoint.adalasso.changepoints_utils import estimate_seasonality_with_detected_changepoints
  from greykite.algo.changepoint.adalasso.changepoints_utils import estimate_trend_with_detected_changepoints
  from greykite.algo.changepoint.adalasso.changepoints_utils import filter_changepoints
  from greykite.algo.changepoint.adalasso.changepoints_utils import find_neighbor_changepoints
  from greykite.algo.changepoint.adalasso.changepoints_utils import get_changes_from_beta
  from greykite.algo.changepoint.adalasso.changepoints_utils import get_seasonality_changepoint_df_cols
  from greykite.algo.changepoint.adalasso.changepoints_utils import get_seasonality_changes_from_adaptive_lasso
  from greykite.algo.changepoint.adalasso.changepoints_utils import get_trend_changepoint_dates_from_cols
  from greykite.algo.changepoint.adalasso.changepoints_utils import get_trend_changes_from_adaptive_lasso
  from greykite.algo.changepoint.adalasso.changepoints_utils import get_yearly_seasonality_changepoint_dates_from_freq
  from greykite.algo.changepoint.adalasso.changepoints_utils import plot_change
  from greykite.common.testing_utils import generate_df_for_tests
label_desc: Use image node_id 18 for calling a global function with example usage: test_get_trend_changepoint_dates_from_cols() without return types