extend list for use with waitBestList

Hey Folks,

I am using a lot of lists like:

list_buttons_green = ["image1.png","image2.png"]
list_buttons_yellow = ["image3.png","image4.png"]

using them inside my script by:

match_ list_buttons_green = waitBestList(1, list_buttons_green)
if match_ list_buttons_green:
  print('found on of my list_buttons_green')

when extending the list by using:

list_buttons_green.extend(list_buttons_yellow)

I thought I could get them both together into one list, but the waitBestList method stops working, when doing so.
same happens when using:
list_buttons_green.append(list_buttons_yellow)

by printing the list, I can see it is working on python level, but looks like sikuli won't get the right information about this list...

any ideas?