code: def _build_encoder_config(self):
      return OmegaConf.create(
          {
              "type": "finetune_faster_rcnn_fpn_fc7",
              "params": {
                  "in_dim": 2048,
                  "weights_file": "models/detectron.defaults/fc7_w.pkl",
                  "bias_file": "models/detectron.defaults/fc7_b.pkl",
                  "model_data_dir": self.config.model_data_dir,
              },
          }
      )
  
imports: import functools
  import logging
  import math
  import torch
  import torch.nn.functional
  from mmf.common.registry import registry
  from mmf.models.base_model import BaseModel
  from mmf.modules.layers import ClassifierLayer
  from mmf.utils.build import build_image_encoder
  from omegaconf import OmegaConf
  from torch import nn
label_desc: Use image node_id 4 for calling the M4C obj's underlying member method code with example usage: obj._build_encoder_config() and returns: OmegaConf