:returns: The username of the user with whom the logged in user is
                  conversing in this :class:`~.MessageThread`.

def correspondent(self):
        """
        :returns: The username of the user with whom the logged in user is
                  conversing in this :class:`~.MessageThread`.
        """
        try:
            return self._correspondent_xpb.one_(self._thread_element).strip()
        except IndexError:
            raise errors.NoCorrespondentError()