Error - Cannot implicitly convert type 'UnityEngine.ContactPoint2D' to 'UnityEngine.Vector2'

Hi, I am new to coding itself and trying to learn Unity. I am coding a simple wall breaker game and my script is to detect collisions in 2D and act appropriately (via the If - else loop).

One of the variables (normal) is a Vector 2 value to collect the last value in the collider.contacts array. I am getting a "Cannot implicitly convert type ‘UnityEngine.ContactPoint2D’ to ‘UnityEngine.Vector2’ error message when I execute the script. I am using the normal variable to check what collider the ball is colliding against in the script. Any help to resolve this issue is most appreciated. Thanks!

using UnityEngine;
using System.Collections;

public class Apple : MonoBehaviour
{
public float velocity=1;
private Vector3 _direction;

// Use this for initialization
void Start () 
{
	float randomValue = Random.Range (-1.0f, 1.0f);
	int xComponent = (int)Mathf.Sign (randomValue);
	_direction = new Vector3 (xComponent, 1, 0);
	_direction.Normalize ();
}

// Update is called once per frame
void Update () 
{
	//GetComponent<Transform> ().position += _direction * velocity;
	transform.position += _direction*velocity*Time.deltaTime;
}

//Detect Collisions
void OnCollisionEnter2D(Collision2D collider)
{
	//checking whether the Apple is colliding with the "ColliderCreator"
	ColliderCreator colliderCreator = collider.gameObject.GetComponent<ColliderCreator> ();

	//checking whether the Apple is colliding with the "Platform"
	Platform platform = collider.gameObject.GetComponent<Platform>();

            Vector2 normal = collider.contacts [0];
	bool isGameOver = false;

	//checking whether the apple is colliding with the wall
	if (colliderCreator != null) 
	{
		if (normal == Vector2.up) //hitting the bottom wall
		{
			isGameOver = true;
		}
	} 
	else if (platform) 
	{
		if (normal != Vector2.up) //if the apple strikes the platform on any side other than "Up"
		{
			isGameOver = true;
		}
	}
	if (isGameOver) 
	{
		//This is Game Over
	}
	else
	//Reflecting the Apple's direction along the normal
	_direction = Vector3.Reflect (_direction, collider.contacts [0].normal);
	_direction.Normalize ();
}

}

Kindly disregard … I was able to solve this issue by myself. I was missing .normal after Vector2 normal = collider.contacts [0]. Thanks.