def METHOD_NAME(self, repeat=0, fold=0, sample=0):
    if repeat not in self.split:
        raise ValueError("Repeat %s not known" % str(repeat))
    if fold not in self.split[repeat]:
        raise ValueError("Fold %s not known" % str(fold))
    if sample not in self.split[repeat][fold]:
        raise ValueError("Sample %s not known" % str(sample))
    return self.split[repeat][fold][sample]