如何在codeigniter的自定义库中设置规则表单验证

class My_Form_validation extends CI_Form_validation {
    public function __construct() {
        parent::__construct();
    }
}

class My_Form_validation extends CI_Form_validation {
    public function __construct() {
        parent::__construct();
    }

    public function custom_validation() {
        $this->set_rules('field_name', 'Field Label', 'required|valid_email');
        // 添加更多的验证规则
    }
}

$this->load->library('my_form_validation');
$this->my_form_validation->custom_validation();

if ($this->form_validation->run() == FALSE) {
    // 验证失败，显示错误信息
    echo validation_errors();
} else {
    // 验证成功，执行其他操作
}