上台阶问题的具体走法用python来实现

n个台阶，一次可以走1步，也可以走2步，有多少种走法，给出具休的走法方案？

def f(n,s=""):
    if n <= 0:
        print("0" + s)
        return
    if n == 1:
        print("0,1" + s)
        return
    f(n-1,"," + str(n) + s)
    f(n-2,"," + str(n) + s)


def f(n,s=""):
    if n <= 0:
        print(','.join(s.split(",")[1:]))
        return
    if n == 1:
        print("1" + s)
        return
    f(n-1,"," + "1" + s)
    f(n-2, ","+ "2" + s)