Set property to all children in container

Phaser 3
1

I have sprites with two frames in a container. I need to reset all of them back to frame 1.

I’ve tried these two methods be neither work. How should this be done?

_this.letterset.setAll(‘frame’, 0);

_this.letterset.children.each(function(let) {
let.setFrame(0);
}, this);

2 
container.each(function(sprite) {
  sprite.setFrame(0);
});

should work. What happens?

Also

container.each(Phaser.GameObjects.Sprite.prototype.setFrame, null, 0);
3

Thanks. I used:

container.each(function(sprite) {
sprite.setFrame(0);
});