How to check if a key is down in editor script

I am writing an editor script and I want to be able to check if a key is or has been pressed regardless of what has focus. I realize that Input won’t work. So far I haven’t been able to find anything in the documentation or on Google that would allow me to do this. I was wondering how to do this or if it is even possible.

[CustomEditor(typeof(yourClassTarget))]
public class yourEditorClass: Editor
{
void OnSceneGUI()
{
VertexPaint script = (VertexPaint)target;
Event e = Event.current;
switch (e.type)
{
case EventType.keyDown:
{
if (Event.current.keyCode == (KeyCode.A))
{
script.Painting = true;
}
break;
}
}
}
}

I know that this post is archeology, but to complete the exemple code of the answer you have to add the instruction e.Use(); after your code.

     [CustomEditor(typeof(yourClassTarget))]
     public class yourEditorClass: Editor
     {
         void OnSceneGUI()
         {
             VertexPaint script = (VertexPaint)target;
             Event e = Event.current;
             switch (e.type)
             {
                 case EventType.keyDown:
                 {
                     if (Event.current.keyCode == (KeyCode.A))
                     {
                         script.Painting = true;
                         // EDIT  : this a the instruction to add. 
                         // You realy need it to avoid performance issues !
                         e.Use();
                         // END EDIT
                     }
                     break;
                 }
             }
         }
     }