text: #!/usr/bin/env python3
  
  # Copyright (c) Facebook, Inc. and its affiliates.
  # This source code is licensed under the MIT license found in the
  # LICENSE file in the root directory of this source tree.
  
  import os
  from parlai.core.build_data import DownloadableFile
  import parlai.core.build_data as build_data
  
  RESOURCES = [
      DownloadableFile(
          'http://parl.ai/downloads/dstc7/dstc7_v2.tgz',
          'dstc7_v2.tgz',
          'cc8fd830f9894768ab4f7b104cddd4105456812ab614041337ec12c5a3a56685',
      )
  ]
  
  
  def build(opt):
      dpath = os.path.join(opt['datapath'], 'dstc7')
      version = '2.0'
  
      if not build_data.built(dpath, version_string=version):
          print('[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              # An older version exists, so remove these outdated files.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_string=version)
  