def date_holiday():
    """
   https://jakevdp.github.io/blog/2015/07/23/learning-seattles-work-habits-from-bicycle-counts/

from pandas.tseries.holiday import USFederalHolidayCalendar
cal = USFederalHolidayCalendar()
holidays = cal.holidays('2012', '2016', return_name=True)
holidays.head()

holidays_all = pd.concat([holidays, "Day Before " + holidays.shift(-1, 'D'),  "Day After "
+ holidays.shift(1, 'D')])
holidays_all = holidays_all.sort_index()
holidays_all.head()

from pandas.tseries.offsets import CustomBusinessDay
from pandas.tseries.holiday import USFederalHolidayCalendar
bday_us = CustomBusinessDay(calendar=USFederalHolidayCalendar())
dateref[-1] - bday_us- bday_us

   """
