《Flask Web开发实战》勘误

def validate_username(self, field):
    if field.data != self.user.username and User.query.filter_by(username=field.data).first():
        raise ValidationError('The username is already in use.')

    if form.validate_on_submit() and current_user.validate_password(form.old_password.data):
        current_user.set_password(form.password.data)  # 重设密码
        db.session.commit()
        flash('Password updated.', 'success')
        return redirect(url_for('.index', username=current_user.username))

    if form.validate_on_submit():  # 验证表单是否通过验证
        if current_user.validate_password(form.old_password.data):  # 验证旧密码
            current_user.set_password(form.password.data)  # 设置新密码
            db.session.commit()  # 提交数据库会话
            flash('Password updated.', 'success')
            return redirect(url_for('.index', username=current_user.username))
        else:
            flash('Old password is incorrect.', 'warning')  # 旧密码不对则显示提示

@admin_bp.route('/lock/user/<int:user_id>', methods=['POST'])
@login_required
@permission_required('MODERATE')