python递归实现字符串逆反

def main():
    string=input("Enter a string:")
    string1=reverse(string)
    print(string+" 's reverse format is "+string1)
def reverse(string):
    if string !=' ':
       return reverseRecursion(string)
    else:
        return string
def reverseRecursion(string):
    if len(string)==2:
        return string[1]+string[0]
    else:
        return string[-1]+reverseRecursion(string[:-1])
main()