code: def __len__(self):
      return len(self.dataset)
  
file_path: chainer/examples/pix2pix/facade_dataset.py
imports: from PIL import Image
  from chainer.dataset import dataset_mixin
  import numpy
label_desc: Use image node_id 2 for calling the FacadeDataset obj's underlying member method code with example usage: obj.__len__() and returns: len