docs: def process(self, sched, coro):
          """Add the given coroutine in the scheduler."""
          super(AddCoro, self).process(sched, coro)
          self.result = sched.add(self.coro, self.args, self.kwargs, self.prio & priority.OP)
          if self.prio & priority.CORO:
              return self, coro
          else:
              sched.active.append( (None, coro))