import datetime def get_month_zone(before_day=1): today = datetime.date.today() day = today.day year = today.year month = today.month if day > before_day: last_day = today - datetime.timedelta(1) else: last_day = datetime.date(year, month, 1) - datetime.timedelta(1) first_day = datetime.date(last_day.year, last_day.month, 1) first_day = first_day.strftime("%Y-%m-%d") last_day = last_day.strftime("%Y-%m-%d") return [first_day, last_day] print(get_month_zone())