code: def safe_index(feature_list, e):
      """
      Return index of element e in list l. If e is not present, return the last index
  
      Parameters
      ----------
      feature_list : list
          Feature vector
      e : int
          Element index to find in feature vector
      """
      try:
          return feature_list.index(e)
      except ValueError:
          return len(feature_list) - 1
  
file_path: deepchem/deepchem/feat/molecule_featurizers/conformer_featurizer.py
imports: import numpy
  from rdkit import Chem
  from rdkit.Chem import AllChem
  from deepchem.feat.graph_data import GraphData
  from deepchem.feat import MolecularFeaturizer
label_desc: Use image node_id 1 for calling a global function with example usage: safe_index(feature_list, e) and returns: feature_list, unknown