code: def byweekday(self):
          
          retval = []
          if self.rule._byweekday:
              retval += [Weekday(day) for day in self.rule._byweekday]
          if self.rule._bynweekday:
              retval += [Weekday(day, n) for day, n in self.rule._bynweekday]
          return retval
docs: The weekdays where the recurrence will be applied.  In RFC5545 this is
          called BYDAY, but is renamed by dateutil to avoid ambiguity.