Animation method/coroutine playable once or loop

I just started to implement a class with some static coroutines which take a sprite as parameter and some other values to make some basic animations (blink, color interpolation, translation, bump, etc.)

An example with the blink :

 static public IEnumerator Blink(tk2dBaseSprite sprite, Color blinkColor, float blinkDuration, int cycles = 1)
         {
             while (cycles > 0)
             {
                 var defaultColor = sprite.color;
                 sprite.color = blinkColor;
                 yield return new WaitForSeconds(blinkDuration);
                 sprite.color = defaultColor;
                 cycles--;
                 yield return new WaitForSeconds(blinkDuration);
             }
             cycles = 0;
         }

Coroutines are very usefull in these cases for me because of the "WaitForSeconds" possibility.

My problem is that I would like a blink which also could possibly loop as a condition is true in an update() function :

 void Update()
 {
    if(conditionForLooping)
    {
       blink()
    }
 }

But, obviously, it won't work with a coroutine. I thought about using a simple method and use bot Invoke() and InvokeRepeating() but I'd lose the "WaitForSeconds" and I'd have to stock a time variable in the class, which doesn't fit with a static method.

So, I feel stuck :) Could anybody help me ?

PS : sorry for my english, I hope my question is clear...