If the dataset is available on the GCS bucket gs://tfds-data/datasets.

def is_dataset_on_gcs(dataset_name):
  """If the dataset is available on the GCS bucket gs://tfds-data/datasets."""
  dir_name = posixpath.join(GCS_DATASETS_DIR, dataset_name)
  return len(gcs_files(prefix_filter=dir_name)) > 2