With such problems - I believe it would be better if they would point out to the documentation 
While there is indeed a possibility to send the message to sprite for it to play the animation I find it strange, when there is a direct call to do it:
sprite.play_flipbook("#sprite", hash("explosion"))
I like that GPT suggests also to delete the objects after - but why with timers? 
It could be deleted when the animation of explosion is done in e.g. callback function on completion 
Also - I would do it with trigger collisions only, as this is enough for such a use case - you don’t need any data about the collision except that it happened