code: def add_business_days(self, days_int, holiday_obj=None):
          
  
          res = self
          if days_int >= 0:
              count = 0
              while count < days_int:
                  res = BusinessDate.add_days(res, 1)
                  if BusinessDate.is_business_day(res, holiday_obj):
                      count += 1
          else:
              count = 0
              while count > days_int:
                  res = BusinessDate.add_days(res, -1)
                  if BusinessDate.is_business_day(res, holiday_obj):
                      count -= 1
  
          return res
docs: private method for the addition of business days, used in the addition of a BusinessPeriod only
  
          :param BusinessDate d:
          :param int days_int:
          :param list holiday_obj:
          :return: BusinessDate