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 *.

Example 1

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