有如下程序段：

class xcal:
    def __init__(self,numx,numy):
        self.numx=numx
        self.numy=numy
    def xadd(self,another):
        numx=self.numx*another.numx
        numy=self.numy*another.numy
        return xcal(numx,numy)
    def print(self):
        print(str(self