python函数（模拟算数游戏）

[code]from operator import add,sub
from random import randint,choice
ops={'+':add,'-':sub}
def init():
    op=choice('+-')#随机返回序列中的元素
    nums=[randint(1,10) for x in range(2)]
    # nums.sort(reverse=True)
    #注意这个*，表示传递一个元组作为参数
    #下面另附一个用字典作为参数调用函数的例子
    ans=ops[op](*nums)
    pr='%d %s %d=' % (nums[0],op,nums[1])
    oops=0;
    while True:
        try:
            if int(input(pr))==ans:
                print('correct')
                break;
            if oops==2:
                print('answrer:\n%s %d'% (pr,ans))
            else :
                print('incorrect... try again')
                oops+=1
        except(KeyboardInterrupt,EOFError,ValueError):
            print('invalid input... try again')
def main():
    while True:
        init()
        try:
            opt=input('Again [y/n]?').lower()
            if opt and opt[0]=='n':
                break
        except(KeyboardInterrupt,EOFError):
            break
if __name__=='__main__':
    main()

[code]def test(**a):
    for x in a:
        print(x,':',a[x])
if __name__=='__main__':
    a={'x':1,'y':2,'z':3}
    test(**a)