201901-relativedelta（weeks = 1）获得201900

Question

很抱歉是否有这样的话题，但我不知道如何提出问题以找到类似的话题。正如我所说的，它将获得201900，而我需要201852。有什么建议吗？谢谢！

from dateutil.relativedelta import relativedelta

year = str(current_date.isocalendar()[0])
wk = str(current_date.isocalendar()[1])
weektoday = year+'0'+wk

neededwk = datetime.datetime.strptime(weektoday, '%Y%w%W')

if datetime.date.today().isoweekday() == 1:
    neededwk = neededwk - relativedelta(weeks=2)
else:
    neededwk = neededwk - relativedelta(weeks=1)

neededwk = neededwk.strftime('%Y%W')

有关详细信息：relativedelta