 the weights from that latest model file. 
          # This function should return --
          # pred_fn: Function that predicts on a batch of input images
          # close_fn: Function that clears up stuff like releasing GPU memory etc.
          # model_file: Model file from which the weights were used. 
          
          self.model = self.create_model()
          
          # Load weights from latest trained model file if model_file is None.
          if model_file is None:
              step, model