Setblock Decorated Pot has a random Pottery Sherd. [2023.4]

Hello everyone! my first turtorial

I create local variables type : string

This is how I do it : https://ibb.co/XC4FzwF

and the code : 

{

        String decorated_pot = "";

        decorated_pot = "" + ForgeRegistries.ITEMS.tags().getTag(ItemTags.create(new ResourceLocation("minecraft:decorated_pot_sherds"))).getRandomElement(RandomSource.create()).orElseGet(() -> Items.AIR);

        if (world instanceof ServerLevel _level)

            _level.getServer().getCommands().performPrefixedCommand(new CommandSourceStack(CommandSource.NULL, new Vec3(x, y, z), Vec2.ZERO, _level, 4, "", Component.literal(""), _level.getServer(), null).withSuppressedOutput(),

                    ("setblock ~ ~ ~ minecraft:decorated_pot[cracked=false,facing=north,waterlogged=false]{sherds:[\"" + "" + decorated_pot + "\",\"" + decorated_pot + "\",\"" + decorated_pot + "\",\"" + decorated_pot + "\"]}"));

    }