python web开发书中案例报错ValueError: View function did not return a，pythonvalueerror,新手在学flask开发，

python web开发书中案例报错ValueError: View function did not return a，pythonvalueerror,新手在学flask开发，

新手在学flask开发，看到《python web开发》第十章的用户资料，
在搞 管理员级别的资料编辑器 那里出问题了，
视图函数抛出异常，不能返回响应
百度，谷歌，sof无果。找好久了没解决，心塞
所以来寻求帮助，谢谢能提供帮助的人
这是整个文件夹
http://pan.baidu.com/s/1kV4sXcr

路由视图views.py：

@main.route('/edit-profile/<int:id>', methods=['GET', 'POST'])@login_required@admin_requireddef edit_profile_admin(id):    user = User.query.get_or_404(id)    form = EditProfileAdminForm(user=user)    if form.validate_on_submit():        user.email = form.email.data        user.username = form.username.data        user.confirmed = form.confirmed.data        user.role = Role.query.get(form.role.data)        user.name = form.name.data        user.location = form.location.data        user.about_me = form.about_me.data        db.session.add(user)        flash('The profile has been updated.')        return redirect(url_for('.user', username=user.username))    form.email.data = user.email    form.username.data = user.username    form.confirmed.data = user.confirmed    form.role.data = user.role_id    form.name.data = user.name    form.location.data = user.location    form.about_me.data = user.about_me    return render_template('edit_profile.html', form=form, user=user)

表单forms.py:

class EditProfileAdminForm(FlaskForm):    email = StringField('Email', validators=[Required(), Length(1, 64),        Email()])    username = StringField('Username', validators=[        Required(), Length(1, 64), Regexp('^[A-Za-z][A-Za-z0-9_.]*$', 0,                                          'Username must have only letters,'                                           'number, dots or underscores')])    confirmed = BooleanField('Confirmed')    role = SelectField('Role', coerce=int)    name = StringField('Real name', validators=[Length(0, 64)])    location = StringField('Location', validators=[Length(0, 64)])    about_me = TextAreaField('About me')    submit = SubmitField('Submit')        def __init__(self, user, *args, **kwargs):        super(EditProfileAdminForm, self).__init__(*args, **kwargs)        self.role.choices = [(role.id, role.name)                             for role in Role.query.order_by(Role.name).all()]        self.user = user            def validate_email(self, field):        if field.data != self.user.email and \                User.query.filter_by(email=field.date).first():            raise ValidationError('Emai already registered.')        def validate_username(self, field):        if field.data !=self.user.username and \                User.query.filter_by(username=field.data).first():            raise ValidationError('Username already in use.')

模板edit_profile.html：

{% extends "base.html" %}{% import "bootstrap/wtf.html" as wtf %}{% block title %}Flasky - Edit Profile{% endblock %}{% block page_content %}<div class="page-header">    <h1>Edit Your Profile</h1></div><div class="col-md-4">    {{ wtf.quick_form(form) }}</div>{% endblock %}

def permission_required(permission):    def decorator(f):        @wraps(f)        def decorated_function(*args, **kwargs):            if not current_user.can(permission):                abort(403)                return f(*args, **kwargs) # 此行缩进错误，应在if语句外        return decorated_function    return decorator

编橙之家文章，