protected function _allowEmpty(Model $model, $field, $value) {
        if (isset($this->_validations[$field]['required'])) {
            $rule = $this->_validations[$field]['required'];
            $required = isset($rule['rule'][1]) ? $rule['rule'][1] : true;

            if ($this->_isEmpty($value)) {
                if ($rule['allowEmpty']) {
                    return true;

                } else if ($required) {
                    return false;
                }
            }
        }

        return false;
    }