class_docstr: Cityscapes Dataloader
code: def __len__(self):
      return len(self.images)
  
file_path: gluon-cv/gluoncv/data/cityscapes.py
imports: import os
  import numpy
  from PIL import Image
  import mxnet
  from .segbase import SegmentationDataset
label_desc: Use image node_id 5 for calling the CitySegmentation obj's underlying member method code with example usage: obj.__len__() and returns: len