def date_to_int(self, dates):
    "\n        calculates number of days between 01/01/0001 and each date in dates\n        date has format '%m/%d/%Y'\n\n        :param dates: Pandas Series\n        :return: list\n        "
    ret = []
    for date in dates:
        date0 = datetime.datetime(year=1, month=1, day=1)
        datex = datetime.datetime.strptime(date, '%m/%d/%Y')
        ret.append((datex - date0).days)
    return ret
calculates number of days between 01/01/0001 and each date in dates
date has format '%m/%d/%Y'

:param dates: Pandas Series
:return: list
def date_to_int(self, dates):
    "\n        calculates number of days between 01/01/0001 and each date in dates\n        date has format '%m/%d/%Y'\n\n        :param dates: Pandas Series\n        :return: list\n        "
    ret = []
    for date in dates:
        date0 = datetime.datetime(year=1, month=1, day=1)
        datex = datetime.datetime.strptime(date, '%m/%d/%Y')
        ret.append((datex - date0).days)
    return ret