code: def holiday_df():
      holiday_df = get_holidays(
          countries=["US"], year_start=2010, year_end=2016
      )["US"]
      # Only keeps non-observed holidays.
      holiday_df = holiday_df[
          ~holiday_df["event_name"].str.contains("Observed")
      ]
      return holiday_df.sort_values(
          by=[EVENT_DF_DATE_COL, EVENT_DF_LABEL_COL]
      ).reset_index(drop=True)
  
file_path: greykite/greykite/tests/algo/common/test_holiday_grouper.py
imports: import pandas
  import pytest
  from greykite.algo.common.holiday_grouper import HolidayGrouper
  from greykite.algo.common.holiday_utils import HOLIDAY_NAME_COL
  from greykite.algo.common.holiday_utils import get_weekday_weekend_suffix
  from greykite.common.constants import EVENT_DF_DATE_COL
  from greykite.common.constants import EVENT_DF_LABEL_COL
  from greykite.common.constants import TIME_COL
  from greykite.common.constants import VALUE_COL
  from greykite.common.data_loader import DataLoader
  from greykite.common.features.timeseries_features import get_holidays
  from greykite.common.python_utils import assert_equal
label_desc: Use image node_id 2 for calling a global function with example usage: holiday_df() and returns: holiday_df