GUI Label & KeyCode Doesn't Work

I’ve been trying to make it so when you press the letter i, the inventory will show up.
I wrote a code that doesn’t give me any errors, but when I press the letter i, the GUI Doesn’t show up

here’s the code:
using UnityEngine;
using System.Collections;

public class GButton : MonoBehaviour {
	public Texture2D texture = null;
	public float x = 0;
	public float y = 0;
	public float x2 = 0;
	public float y2 = 0;
	private bool activeInv = false;
	
	void Update()
	{
		if (Input.GetKeyDown(KeyCode.I))
		{
			if (!activeInv)
			{
				activeInv = true;
			}
			else
			{
				activeInv = false;
			}
		}
	}

	void onGUI()
	{

if (activeInv)
		{
		GUI.Label(new Rect(x,y, x2,y2), texture);
		}
	}
}

You have wrong in onGUI()

onGUI() ---->>>> OnGUI()

O great