code: def _flip(samples):
      return samples
  
file_path: lavis/lavis/datasets/datasets/nlvr_datasets.py
imports: import os
  import random
  from collections import OrderedDict
  from lavis.datasets.datasets.multimodal_classification_datasets import MultimodalClassificationDataset
  from PIL import Image
label_desc: Use image node_id 1 for calling the NLVREvalDataset obj's underlying member method code with example usage: obj._flip(samples) and returns: samples