code: def test_dedup_holiday_dict():
      """Tests dedup_holiday_dict"""
      countries = [
          "UnitedStates",
          "UnitedKingdom",
          "India",
          "France",
          "Ireland",
      ]
      year_start = 2019
      year_end = 2020
      # retrieves separate DataFrame for each country, with list of holidays
      holidays_dict = get_holidays(
          countries, year_start=year_start, year_end=year_end
      )
      # merges country DataFrames, removes duplicate holidays
      holiday_df = dedup_holiday_dict(holidays_dict)
      assert not holiday_df.duplicated().any()
  
      # ensure all country holidays are included
      for country, country_df in holidays_dict.items():
          joined = country_df.merge(
              holiday_df, on=[EVENT_DF_DATE_COL, EVENT_DF_LABEL_COL]
          )
          assert joined.shape[0] == country_df.shape[0]
  
imports: import datetime
  import pandas
  import pytest
  from greykite.algo.forecast.silverkite.forecast_simple_silverkite_helper import cols_interact
  from greykite.algo.forecast.silverkite.forecast_simple_silverkite_helper import dedup_holiday_dict
  from greykite.algo.forecast.silverkite.forecast_simple_silverkite_helper import generate_holiday_events
  from greykite.algo.forecast.silverkite.forecast_simple_silverkite_helper import get_event_pred_cols
  from greykite.algo.forecast.silverkite.forecast_simple_silverkite_helper import patsy_categorical_term
  from greykite.algo.forecast.silverkite.forecast_simple_silverkite_helper import split_events_into_dictionaries
  from greykite.common.constants import EVENT_DEFAULT
  from greykite.common.constants import EVENT_DF_DATE_COL
  from greykite.common.constants import EVENT_DF_LABEL_COL
  from greykite.common.constants import EVENT_INDICATOR
  from greykite.common.features.timeseries_features import get_holidays
label_desc: Use image node_id 2 for calling a global function with example usage: test_dedup_holiday_dict() without return types