code: def train(self, mode=True):
      self.training = mode
      for module in self.children():
          module.train(mode)
      self.base_model.eval()
      return self
  
file_path: vissl/vissl/models/trunks/feature_extractor.py
imports: import logging
  import torch
  import torch.nn
  from vissl.config import AttrDict
  from vissl.models.model_helpers import Identity
  from vissl.models.trunks import get_model_trunk
label_desc: Use image node_id 5 for calling the FeatureExtractorModel obj's underlying member method code with example usage: obj.train(mode) and returns: self