241. Different Ways to Add Parentheses

Given a string of numbers and Operators, return all possible results from computing all the different possible ways to group numbers and operators. The valid operators are +, - and *.

Input: "2-1-1".

((2-1)-1) = 0(2-(1-1)) = 2
Output: [0, 2]
Example 2
Input: "2*3-4*5"
(2*(3-(4*5))) = -34((2*3)-(4*5)) = -14((2*(3-4))*5) = -10(2*((3-4)*5)) = -10(((2*3)-4)*5) = 10
Output: [-34, -14, -10, -10, 10]
class Solution(object):    def diffWaysToCompute(self, input):        """        :type input: str        :rtype: List[int]        """        L = []        for i in input:            if i.isdigit() == 0:                left = diffWaysToCompute(input[:input.index(i)+1])                right = diffWaysToCompute(input[input.index(i)+1:])                for n in left:                    for m in right:                        if i == '+':                            L.append(n + m)                        elif i == '-':                            L.append(n - m)                        elif i == '*':                            L.append(n * m)        if L.count() == 0:            L.append(int(input))        return L
过不了编译就很气（c++代码可以过）
Line 11: NameError: global name 'diffWaysToCompute' is not defined
为什么啊