code: def step(self):
      raise NotImplementedError()
  
file_path: coremltools/coremltools/optimize/torch/base_model_optimizer.py
imports: import logging
  from abc import ABC
  from abc import abstractmethod
  from collections import UserDict
  from typing import Optional
  from typing import Tuple
  import torch
  from coremltools.optimize.torch._utils.python_utils import get_str
  from coremltools.optimize.torch.optimization_config import OptimizationConfig
label_desc: Use image node_id 3 for calling the BaseModelOptimizer obj's underlying member method code with example usage: obj.step() without return types