def METHOD_NAME(self):
    _dataset_sizes = []
    for ds, sr in zip(self.datasets, self.sample_ratios):
        if isinstance(ds.METHOD_NAME, np.ndarray):
            _dataset_sizes.append(np.tile(ds.METHOD_NAME, sr))
        else:
            # Only support underlying dataset with single size array.
            assert isinstance(ds.METHOD_NAME, list)
            _dataset_sizes.append(np.tile(ds.METHOD_NAME[0], sr))
    return np.concatenate(_dataset_sizes)