Cannot read property 'addTilesetImage' of undefined, error!

[XipsAhoy]

I am trying to make a game so I tried to load a tileset, to help me make the game, but when I try to play my game, this shows on the console- ```Cannot read property 'addTilesetImage' of undefined```

This is my code:

```

 

Ball.Level1 = function (game) {};

Ball.Level1.prototype = {

    create: function () {

        

 

        var map;

 

        var layer;

        

        this.map.addTilesetImage('element-h');

        this.map.addTilesetImage('element-w');

 

        this.map = this.game.add.tilemap('map', 32, 32);

    

        this.layer = this.map.createLayer(0);

 

        this.layer.resizeWorld();

 

    }

};

```

this is what I pre-load!

```

        this.load.image('element-w', 'img/element-w.png');

        this.load.image('element-h', 'img/element-h.png');

        this.load.tilemap('map', 'img/Teste.csv');

```

Thank for your help!