Function child doesn't work

Phaser 3
1

I’m trying to duplicate the cherry as per Phaser’s tutorial ‘Making your first game - Stardust’ but it doesn’t work:

var cherry;

cherry = this.physics.add.group(
        {
            key: 'cherry',
            repeat: 6,
            setXY: { x: 400, y: 100, stepX: 70 }
        }
    );

cherry.children.iterate(function (child) {

    child.setBounceY(Phaser.Math.FloatBetween(0.4, 0.8));

});

cherry = this.physics.add.sprite(380, 250, 'cherry');
cherry.setBounce(0.2);
cherry.setSize(40, 40, true);
this.physics.add.collider(cherry, platforms);
2

What are you going to achieve then?
Looks like you instancing differenct object in the same variable (physics group & single sprite), and wanted to work with collider?