def __iter__(self):
        raise NotImplementedError
Add WMAPE Numerator channels for monitoring dataset(s) to
dataset/ETHPy150Open dokipen/whoosh/src/whoosh/reading.py/IndexReader.__iter__--crossover with--dataset/ETHPy150Open lisa-lab/pylearn2/pylearn2/train_extensions/wmape_channel.py/WMapeNumeratorChannel.setup