public function setSafeSearch($value)
    {
        switch ($value) {
            case 'none':
                $this->_params['safeSearch'] = 'none';
                break;
            case 'moderate':
                $this->_params['safeSearch'] = 'moderate';
                break;
            case 'strict':
                $this->_params['safeSearch'] = 'strict';
                break;
            case null:
                unset($this->_params['safeSearch']);
            default:
                require_once 'Zend/Gdata/App/InvalidArgumentException.php';
                throw new Zend_Gdata_App_InvalidArgumentException(
                    'The safeSearch parameter only supports the values '.
                    '\'none\', \'moderate\' or \'strict\'.');
        }
    }