Media Collection Name

The following code snippet:

var params = {
    principal: "AppUser" /* STRING */,
    principalType: "Organization" /* STRING */,
 collectionName: "Media" /* STRING */
};

// no return
Resources["CollectionFunctions"].AddCollectionVisibilityPermission(params);

gives the following error code:

[message: Execution error in service script [ThingName] : Unable to Invoke Service ServiceName on ThingName : Collection [Media does not exist]

What is the correct Collection name for Media Entities? This service worked for both "Things" and "ThingTemplates".

The only information available on the API is:

collectionName - Collection name (Things, Users, ThingShapes, etc.) - STRING