from datetime import datetime


def days_old(date, date_format="%y%m%d"):
    """ Return the number days between today and given date

        :param string date: date to ckeck with
        :param date_format: the format of given 'date' string
    """
    try:
        time_dif = datetime.today() - datetime.strptime(date,date_format)
    except ValueError:
        return None
    return time_dif.days