第几条先挂

first_fail([(1,1),(2,9),(3,3)]) 交回第几条先挂（下标）？

测试工具：check(got, want) 对上交回 OK 否则 FAIL；run_cases(cases)（cases 是 [(got, want)]）交回通过几条；first_fail(cases) 交回第一条没过的下标（全过 -1）。

def check(got, want):
    # 一条断言：对上交回 "OK"，不对交回 "FAIL"
    return "OK" if got == want else "FAIL"


def run_cases(cases):
    # cases: [(got, want)]；交回通过几条
    return sum(1 for got, want in cases if got == want)


def first_fail(cases):
    # 交回第一条没通过的下标（全过交回 -1）
    for i, (got, want) in enumerate(cases):
        if got != want:
            return i
    return -1

print(first_fail([(1, 1), (2, 9), (3, 3)]))