class_docstr: Abstract base class for network backbones.
class_docstr_tok: ["Abstract","base","class","for","network","backbones","."]
docstr: Subclasses must override this method, but adhere to the same return type.
  
  Returns:
      dict[str->Tensor]: mapping from feature name (e.g., "res2") to tensor
docstr_tok: ["Subclasses","must","override","this","method",",","but","adhere","to","the","same","return","type",".","Returns",":","dict","[","str-",">","Tensor","]",":","mapping","from","feature","name","(","e.g.",",","``","res2","''",")","to","tensor"]
code: def forward(self):
      """
      Subclasses must override this method, but adhere to the same return type.
  
      Returns:
          dict[str->Tensor]: mapping from feature name (e.g., "res2") to tensor
      """
      pass
  
file_path: detectron2/detectron2/modeling/backbone/backbone.py
imports: from abc import ABCMeta, abstractmethod
  from typing import Dict
  import torch.nn
  from detectron2.layers import ShapeSpec
label_desc: Use image node_id 2 for calling the Backbone obj's underlying member method code with example usage: obj.forward() without return types