code: def run(self):
          
          if self.stdout:
              sys.stdout.write("extracted json data:\n" + json.dumps(
                  self.metadata, default=to_str) + "\n")
          else:
              extract_dist.class_metadata = self.metadata
docs: Sends extracted metadata in json format to stdout if stdout
          option is specified, assigns metadata dictionary to class_metadata
          variable otherwise.