payment.py

from datetime import date
from dateutil.relativedelta import relativedelta
from itertools import islice

def payment_day(start, period=1):
    last_payment_day = start
    while True:
        next_payment_day = last_payment_day + relativedelta(months=period)
        yield next_payment_day.strftime("%d-%m-%Y")
        last_payment_day = next_payment_day

if __name__ == "__main__":
    today = date.today()
    date_gen = payment_day(today)
    for i in islice(date_gen, 10):
        print(i)