OnWillSaveAssets issue

How can I call a editor script when the unity editor loads a scene?
Some kind of OnAwake equivalent.

Or right before saving is good al well, I found this:
This does not apear to work, the log is not printing when I save the scene:

class SaveManagerEditor extends Editor
{
	function OnWillSaveAssets ()
   	{
   		Debug.Log("SAVING");
   		CheckDuplicates();
   	}
}

The OnWillSaveAssets function needs to be static.

Also it has a return type of String array and takes an array of string.