How to use the pyperformance.benchmarks.bm_richards.Task function in pyperformance

return self.hold()
        elif i.control & 1 == 0:
            i.control //= 2
            return self.release(I_DEVA)
        else:
            i.control = i.control // 2 ^ 0xd008
            return self.release(I_DEVB)


# WorkTask


A = ord('A')


class WorkTask(Task):

    def __init__(self, i, p, w, s, r):
        Task.__init__(self, i, p, w, s, r)

    def fn(self, pkt, r):
        w = r
        assert isinstance(w, WorkerTaskRec)
        if pkt is None:
            return self.waitTask()

        if w.destination == I_HANDLERA:
            dest = I_HANDLERB
        else:
            dest = I_HANDLERA

        w.destination = dest

h.work_in = work.link
            return self.qpkt(work)

        dev = h.device_in
        if dev is None:
            return self.waitTask()

        h.device_in = dev.link
        dev.datum = work.data[count]
        work.datum = count + 1
        return self.qpkt(dev)

# IdleTask


class IdleTask(Task):

    def __init__(self, i, p, w, s, r):
        Task.__init__(self, i, 0, None, s, r)

    def fn(self, pkt, r):
        i = r
        assert isinstance(i, IdleTaskRec)
        i.count -= 1
        if i.count == 0:
            return self.hold()
        elif i.control & 1 == 0:
            i.control //= 2
            return self.release(I_DEVA)
        else:
            i.control = i.control // 2 ^ 0xd008
            return self.release(I_DEVB)

taskWorkArea.qpktCount += 1
        pkt.link = None
        pkt.ident = self.ident
        return t.addPacket(pkt, self)

    def findtcb(self, id):
        t = taskWorkArea.taskTab[id]
        if t is None:
            raise Exception("Bad task id %d" % id)
        return t


# DeviceTask


class DeviceTask(Task):

    def __init__(self, i, p, w, s, r):
        Task.__init__(self, i, p, w, s, r)

    def fn(self, pkt, r):
        d = r
        assert isinstance(d, DeviceTaskRec)
        if pkt is None:
            pkt = d.pending
            if pkt is None:
                return self.waitTask()
            else:
                d.pending = None
                return self.qpkt(pkt)
        else:
            d.pending = pkt

assert isinstance(d, DeviceTaskRec)
        if pkt is None:
            pkt = d.pending
            if pkt is None:
                return self.waitTask()
            else:
                d.pending = None
                return self.qpkt(pkt)
        else:
            d.pending = pkt
            if tracing:
                trace(pkt.datum)
            return self.hold()


class HandlerTask(Task):

    def __init__(self, i, p, w, s, r):
        Task.__init__(self, i, p, w, s, r)

    def fn(self, pkt, r):
        h = r
        assert isinstance(h, HandlerTaskRec)
        if pkt is not None:
            if pkt.kind == K_WORK:
                h.workInAdd(pkt)
            else:
                h.deviceInAdd(pkt)
        work = h.work_in
        if work is None:
            return self.waitTask()
        count = work.datum