Changes

    """Creates and returns a `Dataset` object by featurizing provided files.

    Reads in `inputs` and uses `self.featurizer` to featurize the

    data in these input files.  For large files, automatically shards

    data in these inputs.  For large files, automatically shards

    into smaller chunks of `shard_size` datapoints for convenience.

    Returns a `Dataset` object that contains the featurized dataset.