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
6/20
15/8
10/12
8/15