How to constrain a MatterJS sprite to world bounds

As the subject says, I have a sprite I’ve added to the world. I have keys set up to apply force to the object, so I can move it around. What do I have to do to stop the object from leaving the world?

Existing code

Game.create = function(){
	this.cameras.main.useBounds = false;,,,

	Game.Player = this.matter.add.sprite(,,

    // I thought this would do it, but all it does is generate an error
    // "Cannot read property 'x' of undefined
	this.matter.add.worldConstraint(Game.Player.body, 1, 0.2);

	Game.cursors = this.input.keyboard.createCursorKeys();

Game is just a generic object I’ve created to store all the game data, as I hate adding stuff globally.