public static function get($field_key)
 {
     // Load field value
     if (is_null(self::$option)) {
         self::$option = get_option(self::$option_name);
     }
     $field_value = isset(self::$option[$field_key]) ? self::$option[$field_key] : '';
     // Fallback values
     if ($field_key == 'permalinks_base' && empty($field_value)) {
         $field_value = 'locations';
     }
     if ($field_key == 'permalinks_category' && empty($field_value)) {
         $field_value = 'locations-category';
     }
     // $bias_bounds;
     // $restrict_state;
     // $restrict_postcode;
     // $restrict_suburb;
     // $restrict_street;
     // $language
     // Return
     return $field_value;
 }