TYSM IT WORKS FINALLY but attributes with underscores don't

i'm gonna try to fix that but thanks it says it's <none>
this is the skript:
# ---------- ITEM ATTRIBUTE COMMAND ----------
command /itemattribute <text> <text> [<text>] [<text>]:
trigger:
if player's tool is air:
send "&cYou need to hold an item."
stop
if arg-1 is "add":
set {_attr} to arg-2 parsed as an attribute type
replace all "_" in {_attr} with " "
set {_slot} to arg-3
set {_amount} to arg-4 parsed as number
set {_id} to "minecraft:%{_attr}%"
apply attribute modifier to player's tool:
attribute: {_attr}
id: "%{_id}%"
slot: {_slot}
amount: {_amount}
operation: add_number
send "&aApplied %{_attr}% with %{_amount}% on %{_slot}% slot."
if arg-1 is "remove":
if arg-2 is not set:
send "&cUsage: /itemattribute remove <attribute>"
stop
set {_attr} to arg-2 parsed as an attribute type
replace all "_" in {_attr} with " "
delete {_attr} attribute modifier of player's tool
send "&aRemoved %{_attr}% from held item."
# ---------- ITEM ATTRIBUTE TAB COMPLETION ----------
on tab complete of "/itemattribute":
set tab completions for position 1 to "add" and "remove"
if tab arg-1 is "add" or "remove":
set tab completions for position 2 to "attack_damage", "max_health", "armor", "armor_toughness", "movement_speed", "attack_speed", "knockback_resistance", "luck", "scale", "step_height", "fall_damage_multiplier" and "gravity"
if tab arg-1 is "add":
set tab completions for position 3 to "mainhand_slot_group", "offhand_slot_group", "head_slot_group", "chest_slot_group", "legs_slot_group" and "feet_slot_group"