How to use the @iiif/vocabulary.ExternalResourceType.CANVAS function in @iiif/vocabulary

const m = await import(/* webpackChunkName: "uv-pdf-extension" *//* webpackMode: "lazy" */"./extensions/uv-pdf-extension/Extension") as any;
                const extension = new m.default();
                extension.name = Extension.PDF;
                return extension;
            }
            // [Extension.VIRTEX]: async () => {
            //     const m = await import("./extensions/uv-virtex-extension/Extension") as any;
            //     const extension = new m.default();
            //     extension.name = Extension.VIRTEX;
            //     return extension;
            // }
        };

        this._extensionRegistry = {};

        this._extensionRegistry[ExternalResourceType.CANVAS] = {
            load: this._extensions[Extension.OSD]
        };

        this._extensionRegistry[ExternalResourceType.IMAGE] = {
            load: this._extensions[Extension.OSD]
        };

        this._extensionRegistry[ExternalResourceType.MOVING_IMAGE] = {
            load: this._extensions[Extension.MEDIAELEMENT]
        };

        this._extensionRegistry[ExternalResourceType.PHYSICAL_OBJECT] = {
            load: this._extensions[Extension.VIRTEX]
        };

        this._extensionRegistry[ExternalResourceType.SOUND] = {