url_for参数有什么问题？

Question

我写了一篇描述添加新用户的课程。 但是，当我添加新用户时，我应该转到相同的视图，不幸的是我得到错误：werkzeug.routing.BuildError: ('register_view', {}, None)

class AddUser(BaseView):
    def is_accessible(self):
        return g.user.is_authenticated()
    @expose('/', methods=('GET', 'POST'))
    def register_view(self):
        if not g.user.is_authenticated():
            return redirect(url_for('.login_view'))
        form = RegForm()
        if helpers.validate_form_on_submit(form):
            if db_session.query(User).filter_by(name=form.name.data).count() > 0:
                flash (' A user with this name already exist')
                return redirect(url_for('register_view'))
            if db_session.query(User).filter_by(email=form.email.data).count() > 0:
                flash (' A user with this email already exist')
                return redirect(url_for('register_view'))
            u = User(form.name.data, form.email.data, hashlib.md5(form.password.data.encode('utf-8')).hexdigest())
            db_session.add(u)
            db_session.commit()
            flash('User has ben added - ' + str(form.name.data))
            return redirect(url_for('register_view'))
        self._template_args['form'] = form
        return self.render('admin/register.html')