code: def enable_cache():
      
      try:
          import requests_cache
      except ImportError as err:
          sys.stderr.write('Failed to enable cache: {0}\n'.format(str(err)))
          return
      if not os.path.exists(CACHE_DIR):
          os.makedirs(CACHE_DIR)
      requests_cache.install_cache(CACHE_FILE)
docs: Enable requests library cache.