Inventory does not contain a definition for inven ... but it does

I have 2 scripts. On called Inventory and one called PickUp. I am getting the error: error CS1061: Type Inventory’ does not contain a definition for Inven' and no extension method Inven’ of type Inventory’ could be found. Are you missing an assembly reference? Here is the inventory script :

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;

public class Inventory : MonoBehaviour {

    public List<Obj> Inven;
    public Image slot1;
    public Image slot2;
    public Image slot3;
    public Image slot4;
    public Image slot5;

    public Obj selectedSlot;

    public int selected;

	// Use this for initialization
	void Start () {
        selected = 0;
	}
	
	// Update is called once per frame
	void Update () {

        selectedSlot = Inven[selected];
        slot3.sprite = selectedSlot.img;

	}
}

and here is the PickUp script :

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;

public class PickUp : MonoBehaviour {

    public Inventory inv;
    public Text txt;
 
    void OnTriggerEnter(Collider other)
    {
        if (Input.GetKey(KeyCode.E))
        {
            if (other.gameObject.CompareTag("Pick Up"))
            {
                inv.Inven.Add(other.GetComponent<Obj>());

                other.gameObject.SetActive(false);
            }
        }
    }
}

and here is the Obj script :

public class Obj : MonoBehaviour {

    public bool IsGrounded;
    public bool IsStable;
    public float hp;
    public string Name;
    public string desc;
    public Sprite img;
	
	// Update is called once per frame
	void Update () {
        if (IsStable == false)
        {
            gameObject.AddComponent<Rigidbody>();
        }

        if (IsGrounded)
        {
            IsStable = true;
        }
	}
}

You seem to have declared your List but not Initialised it.

‘List myList = new List’

The new List bit is important.

So for you:

public List<Obj> Inven = new List<Obj>();