code: def build(opt):
      version = "v1.0"
      dpath = os.path.join(opt["datapath"], "bb3_demo")
  
      if not build_data.built(dpath, version):
          logging.info("building data: " + dpath)
          if build_data.built(dpath):
              # An older version exists, so remove these outdated files.
              build_data.remove_dir(dpath)
          build_data.make_dir(dpath)
  
          # Download the data.
          for downloadable_file in RESOURCES:
              downloadable_file.download_file(dpath)
  
          # Mark the data as built.
          build_data.mark_done(dpath, version)
  
imports: import os
  from parlai.core.build_data import DownloadableFile
  import parlai.core.build_data
  import parlai.utils.logging
label_desc: Use image node_id 1 for calling a global function with example usage: build(opt) without return types