Merge pull request #997 from lilleswing/995-docstring

def load_dataset_from_disk(save_dir):

  """

  Parameters

  ----------

  save_dir: str

  Returns

  -------

  loaded: bool

    Whether the load succeeded

  all_dataset: (dc.data.Dataset, dc.data.Dataset, dc.data.Dataset)

    The train, valid, test datasets

  transformers: list of dc.trans.Transformer

    The transformers used for this dataset

  """

  train_dir = os.path.join(save_dir, "train_dir")

  valid_dir = os.path.join(save_dir, "valid_dir")

  test_dir = os.path.join(save_dir, "test_dir")

  if os.path.exists(train_dir) and os.path.exists(valid_dir) and os.path.exists(

      test_dir):

  if not os.path.exists(train_dir) or not os.path.exists(

      valid_dir) or not os.path.exists(test_dir):

    return False, None, list()

  loaded = True

  train = deepchem.data.DiskDataset(train_dir)

  valid = deepchem.data.DiskDataset(valid_dir)

  all_dataset = (train, valid, test)

  with open(os.path.join(save_dir, "transformers.pkl"), 'rb') as f:

    transformers = pickle.load(f)

  else:

    loaded = False

    all_dataset = None

    transformers = []

    return loaded, all_dataset, transformers