Launch ios custom url app scheme

How can I start with ionic 2 apps on ios. On Android I can run the apps by using the name of package. How can I do the same case on ios the to?

example for image gallery:

schemes: IAppLauncherScheme = {
        appName: "Image Gallery",
        iosScheme: "gallery://",
        androidScheme: "",

gallery:// doen’t work on ios. what is the correct scheme to launch the image gallery on ios?