Why is my for loop ending after the first term?

very new coder here. I’m trying to solve the classic twonums LeetCode problem (https://leetcode.com/problems/two-sum/) using some of the basics I have learned so far. I can get my program to find the indices of the solutions, but can’t seem to make it recognize when the indices are the same and ignore that solution. Most likely I am just not ready for this problem yet, but I’m curious if it’s possible with these tools and I’m missing something. Any and all help is appreciated.

num = [3, 3]
target = 6
def twonum(num):
    for x in num:
        for y in num:
            a = num.index(x)
            b = num.index(y)
            if (x + y == target) and (a != b):
                return(f'{b, a}')
                break
ans = twonum(num)
print(ans)

>Solution :

num.index(x) gives you the first index of x in num, which may not be what you want if there are multiple occurrences. Try replacing:

    for x in num:
        for y in num:
            a = num.index(x)
            b = num.index(y)

with:

    for a, x in enumerate(num):
        for b, y in enumerate(num):