Error with tweens

I get an error trying to use a dissolve shader to destroy the cards in the last line

func play()->void:
#Evita que no haya una carta asignada
if not card:
return
card.play(targets, player_stats)

#Destruir la carta
container.material=DISSOLVE
if tween_destroy and tween_destroy.is_running():
	tween_destroy.kill()
tween_destroy = create_tween().set_ease(Tween.EASE_IN_OUT).set_trans(Tween.TRANS_CUBIC)
tween_destroy.tween_property(material, "shader_parameter/dissolve_value", 0.0, 2.0).from(1.0)

It says that the p_targuet its null, why it happens?

There is no “p_targuet” in the code you provided, so it will make things difficult to help.