d=datetime.date.today()
delta=datetime.timedelta(days=1)
fecha_inicio_semana=d-(delta*(d.isoweekday()-1))
Warning, for the the non-ISO calendars such as UK/USA: the function isoweekday assumes that the first day of the week is Monday.
d=datetime.date.today()
delta=datetime.timedelta(days=1)
fecha_inicio_semana=d-(delta*(d.isoweekday()-1))