docs: def getstruct(self, msgid, as_json=False, stream=sys.stdout):
          """Get and print the whole message.
  
          as_json indicates whether to print the part list as JSON or not.
          """
          parts = [part.get_content_type() for hdr, part in self._get(msgid)]
          if as_json:
              print(json.dumps(parts), file=stream)
          else:
              for c in parts:
                  print(c, file=stream)