#!/usr/bin/env python
# coding=utf-8
class Calculator(object):
is_raise = False
def calc(self, express):
try:
return eval(express)
except ZeroDivisionError:
if self.is_raise:
print "zero can not be division."
else:
raise
if __name__ == "__main__":
c = Calculator()
c.is_raise = True
print c.calc("8/0")