def first_day_of_next_month(self, old_date):

         old_date = datetime.datetime.strptime(old_date, "%Y-%m-%d")

         next_month = old_date.replace(day=28) + datetime.timedelta(days=4)

         next_month = next_month.replace(day=1)

         return next_month.strftime("%Y-%m-%d")

     def last_day_of_month(self, any_day):

         any_day = datetime.datetime.strptime(any_day, "%Y-%m-%d")

         next_month = any_day.replace(day=28) + datetime.timedelta(days=4)  # this will never fail

         return (next_month - datetime.timedelta(days=next_month.day)).strftime("%Y-%m-%d")

     def get_last_day(self, current_date):

         current_date = datetime.datetime.strptime(current_date, "%Y-%m-%d")

         last_date = current_date + datetime.timedelta(days=1)

         return last_date.strftime("%Y-%m-%d")