code: def _handle_BYWEEKDAY(self, rrkwargs, name, value, **kwargs):
          
          l = []
          for wday in value.split(','):
              if '(' in wday:
                  # If it's of the form TH(+1), etc.
                  splt = wday.split('(')
                  w = splt[0]
                  n = int(splt[1][:-1])
              elif len(wday):
                  # If it's of the form +1MO
                  for i in range(len(wday)):
                      if wday[i] not in '+-0123456789':
                          break
                  n = wday[:i] or None
                  w = wday[i:]
                  if n:
                      n = int(n)
              else:
                  raise ValueError("Invalid (empty) BYDAY specification.")
  
              l.append(weekdays[self._weekday_map[w]](n))
          rrkwargs["byweekday"] = l
docs: Two ways to specify this: +1MO or MO(+1)