Example Health Gain Code Item

public TypedActionResult<ItemStack> use(World world, PlayerEntity playerEntity, Hand hand, StatusEffect effect) {
        effect.addAttributeModifier(EntityAttributes.GENERIC_MAX_HEALTH, "5D6F0BA2-1186-46AC-B896-C61C5CEE99CC",
                (amount)D, EntityAttributeModifier.Operation.ADDITION);
        return TypedActionResult.success(playerEntity.getStackInHand(hand));
    }