class_docstr: A base class to support exporting through ONNX
docstr: If the model needs additional preprocessing, e.g., using sequence features,
  returns the config here.
code: def feature_config(self) -> Optional[rlt.ModelFeatureConfig]:
      """
      If the model needs additional preprocessing, e.g., using sequence features,
      returns the config here.
      """
      return None
  
file_path: ReAgent/reagent/models/base.py
imports: from copy import deepcopy
  from typing import Any, Optional
  import torch.nn
  from reagent.core import types
label_desc: Use image node_id 2 for calling the ModelBase obj's underlying member method code with example usage: obj.feature_config() and returns: None