Returns SplitGenerators.

def _split_generators(self, dl_manager):
    """Returns SplitGenerators."""
    # Download images and annotations that come in separate archives.
    # Note, that the extension of archives is .tar.gz even though the actual
    # archives format is uncompressed tar.
    dl_paths = dl_manager.download_and_extract({
        "images": tfds.download.Resource(
            url=os.path.join(_BASE_URL, "102flowers.tgz"),
            extract_method=tfds.download.ExtractMethod.TAR),
        "labels": os.path.join(_BASE_URL, "imagelabels.mat"),
        "setid": os.path.join(_BASE_URL, "setid.mat"),
    })

    gen_kwargs = dict(
        images_dir_path=os.path.join(dl_paths["images"], "jpg"),
        labels_path=dl_paths["labels"],
        setid_path=dl_paths["setid"],
    )

    return [
        tfds.core.SplitGenerator(
            name=tfds.Split.TRAIN,
            num_shards=1,
            gen_kwargs=dict(split_name="trnid", **gen_kwargs)),
        tfds.core.SplitGenerator(
            name=tfds.Split.TEST,
            num_shards=1,
            gen_kwargs=dict(split_name="tstid", **gen_kwargs)),
        tfds.core.SplitGenerator(
            name=tfds.Split.VALIDATION,
            num_shards=1,
            gen_kwargs=dict(split_name="valid", **gen_kwargs)),
    ]