def pair_sum_to_zero(input_list, target):
    index_dict = dict()
    for index, element in enumerate(input_list):
        if target - element in index_dict:
            return [index_dict[target - element], index]
        index_dict[element] = index


def test_function(test_case):
    output = pair_sum_to_zero(test_case[0], test_case[1])
    print(output)
    if sorted(output) == test_case[2]:
        print("Pass")
    else:
        print("Fail")

test_case_2 = [[10, 5, 9, 8, 12, 1, 16, 6], 16, [0, 7]]
test_function(test_case_2)