Hi,

from datetime import datetime
from dateutil.relativedelta import relativedelta

def _add_month_date(self, date_octroi,nbr_echeance) :
    date_before_month = datetime.strptime(date_octroi, '%Y-%m-%d') 
    date_after_month = date_before_month+ relativedelta(months=nbr_echeance)
    return  date_after_month

This function takes as parameters your date and number of months and add return months to this date then return a new date.

thanks.