Convert a Lock identifier into an actual Lock instance.
        @param lockid: a locks.MasterLock or locks.WorkerLock instance
        @return: a locks.RealMasterLock or locks.RealWorkerLock instance

def getLockByID(self, lockid):
        """Convert a Lock identifier into an actual Lock instance.
        @param lockid: a locks.MasterLock or locks.WorkerLock instance
        @return: a locks.RealMasterLock or locks.RealWorkerLock instance
        """
        assert isinstance(lockid, (locks.MasterLock, locks.WorkerLock))
        if lockid not in self.locks:
            self.locks[lockid] = lockid.lockClass(lockid)
        # if the master.cfg file has changed maxCount= on the lock, the next
        # time a build is started, they'll get a new RealLock instance. Note
        # that this requires that MasterLock and WorkerLock (marker) instances
        # be hashable and that they should compare properly.
        return self.locks[lockid]