Returning the Indices of numbers in an array that sums to a particular number

from itertools import permutations as perm

def TwoSum(arr, target):
    L1 = perm(arr, 2)

    for i in L1:
        if sum(i) == target:
            return [arr.index(i[0]), arr.index(i[1])]

var = TwoSum([3,2,4], 6)
print(var)