Change day from next to past

[ghost]

Hello,
Is it Possible to change the day to result in past not future?
E.g.
from timefhuman import timefhuman now = datetime.datetime(year=2019, month=9, day=8) s=timefhuman("Friday",now=now)
This would give this :
datetime.datetime(2019, 9, 13, 0, 0)
which is the next Friday. So is it possible to change the next to the past to give the date of the last Friday without adding any expression to indicate the past.