Just starting with godot but have past experience coding. Right now I am creating a top down shooter, but having weird issues with adding to a group. I have a player class that calls

func ready():
	yield(get_tree(), "idle_frames")
	get_tree().call_group("zombies", "set_player", self)

In my zombies script I put

func ready():
	add_to_group("zombies")

However the set_player method is not being called at all. I have added the zombies scene to a group in the GODOT engine and that didn't help either. Not really sure why this is happening. If you all need any more info let me know.

I don't think yielding from within _ready() makes any sense. ready gets usually called only once. Instead of yielding perhaps it just makes sense to call the next line via call_deferred() or set_deferred() instead.