returning index from a list

Question

I want to return the index(0) from the list in the shown code but it returns None and when I tried to print index(0) it printed 1 so I want to know how to return the index

class Solution:
    def lastStoneWeight(self, stones) ->int:
        if len(stones) ==1:
            print(stones[0])
            return stones[0]
        s = max(stones)
        stones.remove(s)
        v = max(stones)
        stones.remove(v)
        l = s-v
        stones.append(l)
        
       
        self.lastStoneWeight(stones)

list = [2,7,4,1,8,1]
s = Solution()
print(s.lastStoneWeight(list))

The print(stones[0]) is just for debgging

I tried to return the first index of the list but it returned None and I was expecting it to return the index because when I used the function print() it worked!