Commit user and private role in a single DB transaction

        Create a new user.

        """

        self._error_on_duplicate_email(email)

        user = self.model_class(email=email)

        user = User(email=email)

        if password:

            user.set_password_cleartext(password)

        else:

        else:

            # Activation is off, every new user is active by default.

            user.active = True

        self.session().add(user)

        try:

        session = self.session()

            with transaction(session):

                session.commit()

            # TODO:?? flush needed for permissions below? If not, make optional

        session.add(user)

        try:

            # Creating a private role will commit the session

            user.attempt_create_private_role()

        except exc.IntegrityError as db_err:

            raise exceptions.Conflict(str(db_err))

        self.app.security_agent.create_user_role(user, self.app)

        return user

    def delete(self, user, flush=True):