Fixing small bug in datasets

import numpy as np

import pandas as pd

import multiprocessing as mp

from random import shuffle

import random

from functools import partial

from deepchem.utils.save import save_to_disk

from deepchem.utils.save import load_from_disk

            self.data_dir, basename_j, tasks, X_j, y_j, w_j, ids_j)

        assert len(self) == len_data

      # Now shuffle order of rows in metadata_df

      shuffle(metadata_rows)

      random.shuffle(metadata_rows)

      self.metadata_df = Dataset.construct_metadata(metadata_rows)

      self.save_to_disk()