code: def check_dataset_exist(dirpath):
      if not os.path.exists(dirpath):
          print("Please download the malaria dataset first")
          sys.exit(0)
      return dirpath
  
file_path: singa/examples/malaria_cnn/data/malaria.py
imports: import numpy
  import os
  import sys
  from PIL import Image
label_desc: Use image node_id 4 for calling a global function with example usage: check_dataset_exist(dirpath) and returns: dirpath