Added return type annotation for pad functions

from deepchem.utils.molecule_feature_utils import one_hot_encode

from deepchem.utils.typing import RDKitMol, RDKitAtom

import numpy as np

from typing import Tuple

from typing import Tuple, Any

from dataclasses import dataclass

# try:

#   from rdkit.Chem import AllChem

#   from rdkit import Chem

# except:

#   raise ModuleNotFoundError('This class requires RDKit to be installed.')

@dataclass

    return node_features, adj_matrix, dist_matrix

  def pad_array(self, array, shape):

  def pad_array(self, array: np.ndarray, shape: Any) -> np.ndarray:

    """

    Pads an array to the desired shape.

    result[slices] = array

    return result

  def pad_sequence(self, sequence):

  def pad_sequence(self, sequence: np.ndarray) -> np.ndarray:

    """

    Pads a given sequence using the pad_array function.