code: def is_business_day(self, holiday_obj=None):
          
          y, m, d = BusinessDate.to_ymd(self)
          if weekday(y, m, d) > FRIDAY:
              return False
          holiday_list = holiday_obj if holiday_obj is not None else DEFAULT_HOLIDAYS
          if self in holiday_list:
              return False
          elif date(y, m, d) in holiday_list:
              return False
          return True
docs: :param list holiday_obj : datetime.date list defining business holidays
          :return: bool
  
          method to check if a date falls neither on weekend nor is holiday