docs: def _parse_tag(self, name):
          """Parse a tag command."""
          from_ = self._get_from(b'tag')
          tagger = self._get_user_info(b'tag', b'tagger',
                  accept_just_who=True)
          message = self._get_data(b'tag', b'message')
          return commands.TagCommand(name, from_, tagger, message)