code: def forward_for_roi_head(self, features: List, proposal_boxes: List):
      box_features = self.roi_heads._shared_roi_transform(
          features, proposal_boxes
      )
      feature_pooled = box_features.mean(dim=[2, 3])  # pooled to 1x1
      return feature_pooled
  
file_path: mmf/mmf/models/frcnn.py
imports: from typing import List
  import omegaconf
  import torch
  from torch import nn
  from torch.nn import functional
label_desc: Use image node_id 4 for calling the GeneralizedRCNN obj's underlying member method code with example usage: obj.forward_for_roi_head(features, proposal_boxes) and returns: feature_pooled