var target : Transform;
    function Update () {
        // the target object does not refer to the same object as our transform
        if (target != transform) {
            print("Another object");            
        }
    }

using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
    public Transform target;
    void Update() {
        if (target != transform)
            print("Another object");
        
    }
}

import UnityEngine
import System.Collections

class example(MonoBehaviour):

    public target as Transform

    def Update():
        if target != transform:
            print('Another object')