code: def get_gradient(self):
      raise NotImplementedError
  
file_path: DiCE/dice_ml/model_interfaces/base_model.py
imports: import pickle
  import numpy
  from dice_ml.constants import ModelTypes
  from dice_ml.utils.exception import SystemException
  from dice_ml.utils.helpers import DataTransfomer
label_desc: Use image node_id 4 for calling the BaseModel obj's underlying member method code with example usage: obj.get_gradient() without return types