code: def out_feature_channels(self):
      # the current backbones will output the number of channels for each stage
      # even if that stage is not in the out_features list.
      return {
          stage: self.num_features[i]
          for i, stage in enumerate(self.stage_names)
      }
  
imports: import enum
  import inspect
  from typing import Iterable, List, Optional, Tuple, Union
label_desc: Use image node_id 8 for calling the BackboneMixin obj's underlying member method code with example usage: obj.out_feature_channels() and returns: unknown