def test_cutoff(labels,
                scores,
                cutoff,
                metric = "accuracy"):

    """
    -- DESCRIPTION --
    Function to calculate accuracy or false positive rate for a specific cutoff
    value.
      PARAMS:
        - labels (list of strings): list of labels ("active" or "inactive")
        - scores (list of int): list of scores
            NOTE: labels[i] has to corresponds to scores[i]
        - cutoff (int): cutoff value
        - metric (string): one of "accuracy", "fpr" -> the metric to be returned
      RETURNS:
        - accuracy or false positive rate (float)
    """

    predicted = ["active" if score >= cutoff else "inactive" for score in scores]
    agreement = 0
    FP = 0
    N = 0

    for j, label in enumerate(labels):
        if label == predicted[j]:
            agreement = agreement + 1
        if label == "inactive":
            N = N + 1
        if predicted[j] == "active":
            if label == "inactive":
                FP = FP + 1

    accuracy = agreement / len(labels)
    fpr = FP / N

    if metric == "accuracy":
        return accuracy
    elif metric == "fpr":
        return fpr
    else:
        return None