def create_session(self, username, prekeybundle, autotrust=False):
        """
        :param username:
        :type username: str
        :param prekeybundle:
        :type prekeybundle: PreKeyBundle
        :return:
        :rtype:
        """
        logger.debug("create_session(username=%s, prekeybunder=[omitted], autotrust=%s)" % (username, autotrust))
        session_builder = SessionBuilder(self._store, self._store, self._store, self._store, username, 1)
        try:
            session_builder.processPreKeyBundle(prekeybundle)
        except UntrustedIdentityException as ex:
            if autotrust:
                self.trust_identity(ex.getName(), ex.getIdentityKey())
            else:
                raise exceptions.UntrustedIdentityException(ex.getName(), ex.getIdentityKey())