code: def _get_layer(model, key_list):
      if key_list is None:
          return None
  
      a = model
      for key in key_list:
          a = a._modules[key]
  
      return a
  
file_path: tensorwatch/tensorwatch/saliency/gradcam.py
imports: import torch
  from .backprop import VanillaGradExplainer
label_desc: Use image node_id 1 for calling a global function with example usage: _get_layer(model, key_list) and returns: a, None