无法为电子邮件验证设置错误消息 - Zend-form

$email = new Zend_Form_Element_Text('email');
$email->addValidator('EmailAddress', false, array('messages' => '请输入有效的电子邮件地址'));

class My_Validate_Email extends Zend_Validate_Abstract
{
    const INVALID_EMAIL = 'invalidEmail';

    protected $_messageTemplates = array(
        self::INVALID_EMAIL => '请输入有效的电子邮件地址'
    );

    public function isValid($value)
    {
        $this->_setValue($value);

        if (!filter_var($value, FILTER_VALIDATE_EMAIL)) {
            $this->_error(self::INVALID_EMAIL);
            return false;
        }

        return true;
    }
}

$email = new Zend_Form_Element_Text('email');
$email->addValidator(new My_Validate_Email());

$translate = new Zend_Translate(
    array(
        'adapter' => 'array',
        'content' => array('invalidEmail' => '请输入有效的电子邮件地址'),
        'locale' => 'zh_CN'
    )
);

$email = new Zend_Form_Element_Text('email');
$email->addValidator('EmailAddress', false, array('messages' => $translate->_('invalidEmail')));