Recipe –Calfiles- persistency
        Cal541 = BiasFrame(pathname=targetname)
        Cal541.inframe = raw_frames
        Cal541.make()
        # Verify the result by comparing with a previous version
        if previous_bias != None:
            Cal541.prev = BiasFrame(pathname=previous_bias)
            if target.verify():
                Message('New master bias is not within range of the
previous one.')