python为什么这不起作用

Question

from math import factorial
import math
def get_bernoulli(n):
    b = 0
    sum = 0
    for k in range (0, n-1):
        part = (factorial(n)) / factorial(k) * factorial(n+1 - k)))*b
        sum += part
        b = -(1/n+1)*sum

pycharm抱怨n k和b。它显示未解决的参考。这意味着什么？

Answer 1

让我们来计算这一行中的括号：

part = (factorial(n)) / factorial(k) * factorial(n+1 - k)))*b

• 4x - “（”
• 6x - “）”