怎样学好一门编程语言

计算阶层加减，空白处应该怎么填才能保证它运行啊。实在是填不来

s=0

def jieCheng(n):
    f = 1
    for i in range(1, n+1):
        f *= i
    return f

s = 0
for i in range(1, 10, 2):
    s += jieCheng(i)

print("1!+3!+5!+...+9! =", s)