Making a List for Inventory System, Got an error in finding constructors and variables

Hello everyone, I am currently following tutorials on making an Inventory system for my game. Right now I have a code for my Item (IS_ItemHandler) and an Inventory Management code (IS_Items). I made a public class in ItemHandler with variables and an itemsList in Items calling those variables.

I have copied the tutorials exactly, but it is 2 years old. So did a Unity update cause this error? I am teaching myself Javascript and still heavily an amateur. Sorry if my coding vocab is off.

I am getting this error: Assets/My Assets/Javascript/IS_Items.js(19,34): BCE0024: The type 'ItemHandler' does not have a visible constructor that matches the argument list '(int, UnityEngine.Texture2D, String, String, boolean, ItemType, Rarity)'.

Let me know if you need for details. Thank you!

Here are both of my codes:

IS_ItemHandler -

 public class ItemHandler
 {
 var itemID : int;
 var icon : Texture2D;
 var name : String;
 var description : String;
 var equipped : boolean = false;
 var itemType : ItemType;
 var rare : Rarity;
 }
 
 function ItemHandler(ID : int, ItemIcon : Texture2D, ItemName : String, ItemDescription : String, Equipped : boolean, Type : ItemType, Rareness : Rarity)
 {
 this.itemID = ID;
 this.icon = ItemIcon;
 this.name = ItemName;
 this.description = ItemDescription;
 this.equipped = Equipped;
 this.itemType = Type;
 this.rare = Rareness;
 }
 
 
 enum ItemType
 {
     Battery,
     Health,
     Door,
     Leftarm,
     Rightarm,
     Leftleg,
     Rightleg,
     Brain,
     TwoHands,
     OneHand
 };
 
 enum Rarity
 {
     Verycommon,
     common,
     uncommon,
     lore,
     rare,
     veryrare,
     extremerare,
     prime
 };
 
 

IS_Items

 import System.Collections.Generic;
 var itemsList : List.<ItemHandler> = new List.<ItemHandler>();
 
 private var item1Icon : Texture2D;
 private var item2Icon : Texture2D;
 private var item3Icon : Texture2D;
 
 function Start () 
 {    
     //Icons Items Start
     item1Icon = Resources.Load("Items/Item1", Texture2D);
     item2Icon = Resources.Load("Items/Item2", Texture2D);
     item3Icon = Resources.Load("Items/Item3", Texture2D);
     //Icons Items End
 
     //Items Start
     //ID int, Icon Texture, Name String, Desc. String, Equip Boolean, Type ItemType, rarityList Rarity
     //0
     itemsList.Add(ItemHandler(1, item1Icon, "Battery", "Battery's Mock Description.", false, ItemType.Battery, Rarity.Verycommon));
 }