$options = array(
        array(
            'id' => 'checkbox1',
            'type' => 'checkbox',
            'page' => 'page1',
         ),
        array(
            'id' => 'checkbox2',
            'type' => 'checkbox',
            'page' => 'page1',
         ),
);

function setting_validate($input) {
           foreach($options as $setting) {
             if($setting['type'] == "checkbox") {
                $valid_input[$setting] = ( isset( $input[$setting] ) && true == $input[$setting] ? true : false );
             }
           }

           $options = get_option('XX_theme_settings');
           $merged = array_merge($options, $input);
           return $merged;
        }