Get the stream object using stream_id in tokbox

I want to create a stream object that I can pass on to a forcemuteStream method. I currently have the stream_id, does anyone knows how to do please? the stream_id is a string. My final method looks like below:

    session.forceMuteStream(stream)
        .catch(function() {
            alert("Mute Individual OK")
        }).catch(function(error) {
        console.log("Error: ", error);
    });