Is the animation named name playing?

	// Plays an animation only if we are not playing it already.
	function OnMouseEnter() {
		if (!animation.IsPlaying("mouseOverEffect"))
			animation.Play("mouseOverEffect");
	}

using UnityEngine;
using System.Collections;

public class Example : MonoBehaviour {
    void OnMouseEnter() {
        if (!animation.IsPlaying("mouseOverEffect"))
            animation.Play("mouseOverEffect");
        
    }
}

import UnityEngine
import System.Collections

public class Example(MonoBehaviour):

	def OnMouseEnter() as void:
		if not animation.IsPlaying('mouseOverEffect'):
			animation.Play('mouseOverEffect')