写一个函数，检测输入的数字旋转180度后是否相等，比如619旋转后还是619.

用递归的方法很容易实现：

#coding=utf-8

def turnover(n):
    if len(n) == 0:
        return True
    elif len(n) == 1:
        return n in '018'
    elif (n[0]==n[-1] and n[0] in '018') \
         or n[0]+n[-1] in '969':
        return turnover(n[1:-1])
    else:
        return False

test_cases = """0 1 6 8 9 10 11 18 69 80 88 
91 96 99 100 101 111 121  619 916 6699 18181 """

for test_num in test_cases.split():
    print(test_num, turnover(test_num))#coding=utf-8

def turn