Extending WP_JSON_CustomPostType gives

Error message:
Catchable fatal error: Argument 1 passed to WP_JSON_CustomPostType::__construct() must implement interface WP_JSON_ResponseHandler, none given, called in /var/www/wp-content/plugins/... on line 12 and defined in /var/www/wp-content/plugins/json-rest-api/lib/class-wp-json-customposttype.php on line 31

Code:

function osd_api() {
	global $osd_api;

	$osd_api = new OSD_API();
	add_filter( 'json_endpoints', array( $osd_api, 'register_routes' ) );
}
add_action( 'plugins_loaded', 'osd_api' );

class OSD_API extends WP_JSON_CustomPostType {
	protected $base = '/swimmers';
	protected $type = 'swimmer';

	function register_routes( $routes ) {
		$routes = parent::registerRoutes( $routes );

		return $routes;
	}
}

I’ve tryed to follow your guide here but it also gives me the error message even if I change my code to the example code (the second one).

https://www.ads-software.com/plugins/json-rest-api/