[leetcode, python] Two Sum 两数之和等于某数

Given an array of integers, return indices of the two numbers such that they add up to a specific target.

You may assume that each input would have exactly one solution, and you may not use the same element twice.
Example:
Given nums = [2, 7, 11, 15], target = 9,
Because nums[0] + nums[1] = 2 + 7 = 9,
return [0, 1].

class Solution(object):
def twoSum(self, nums, target):
"""
:type nums: List[int]
:type target: int
:rtype: List[int]
"""
for i, num in enumerate(nums):
sub_num = target - num
if sub_num in nums:
t_index = nums.index(sub_num)
if t_index != i:
return [i, t_index]