'Returns a (TP, TN, FP, FN)-tuple for the given class (one-vs-all).'

def __call__(self, target):

    TP = 0
    TN = 0
    FP = 0
    FN = 0
    for t1 in self:
        for (t2, n) in self[t1].items():
            if (target == t1 == t2):
                TP += n
            if (target != t1 == t2):
                TN += n
            if (target == t1 != t2):
                FN += n
            if (target == t2 != t1):
                FP += n
    return (TP, TN, FP, FN)
