human
Here's a good function header given the following:
I wrote the below code

    def _score(g_tokens, a_tokens):
        common = (Counter(g_tokens) & Counter(a_tokens))
        num_same = sum(common.values())
        if (num_same == 0):
            return 0
        precision = ((1.0 * num_same) / len(g_tokens))
        recall = ((1.0 * num_same) / len(a_tokens))
        f1 = (((2 * precision) * recall) / (precision + recall))
        return f1
    if ((guess is None) or (answers is None)):
        return 0
    g_tokens = _normalize_answer(guess).split()
    scores = [_score(g_tokens, _normalize_answer(a).split()) for a in answers]
    return max(scores)

What's a good function header?
assistant
#Here's a good function header.

def _f1_score(guess, answers):