processFrontMatter return data

I an trying to use the newish app.fileManager.processFrontMatter method I would like to request that “return” would pass through data and let processFrontMatter return that data

Use case or problem

function test () {
    let Global_Data = app.vault.getAbstractFileByPath("z. Global Assets/");
    return app.fileManager.processFrontMatter(Global_Data, (fm) => {
        fm["System"] = "new test 001";
		return fm["System"];
module.exports = test;

Proposed solution

The "(fm) => " lambda should be able to return fm then if it does the processFrontMatter method should return that data so it could be used for whatever.