Scriptum/Assets/Scripts/REFACTORING/Application/Panel/Inventory/InventoryDataListManager.cs

using System.Collections.Generic;
using UnityEngine;

public class InventoryDataListManager : DataListManager<IndexValuePair<int, EquippableItem>> // or maybe EquippableItem - but its get conflicts...
{
    public new DataListManager<IndexValuePair<int, EquippableItem>> SetUiManager(ref InventoryUIManager _uiManager)
    {
        uiManager = _uiManager;

        return this;
    }

    public override void AddElementToList(IndexValuePair<int, EquippableItem> newElement)
    {
        Elements.Add(newElement);
    }

    public override void RemoveElementFromList(IndexValuePair<int, EquippableItem> element)
    {
        throw new System.NotImplementedException();
    }
}