How to close current window by invoking a function from another window

[hoffenmerCode]

Quasi code in class TogaProject:

def startup:

• show app window: main
• inside is a button that calls function: on_press=opeNewWindow

def anotherWindow:

• show new main window window: main

def openNewWindow:

• opens anotherWindow() --> works perfectly
• want to close startup window --> cannot do this!

So I am able to open a new window from 'startup' but at the same time I would like to close the 'startup' window and I cannot. I tried self.startup.close() = error. I tried giving mainWindow in startup an 'id' and then calling that 'id'.close() inside the openNewWindow function but I get an error.

How should this be done properly? Using OSX desktop app. Thanks.

[hoffenmerCode]

Got it:

I used the .window selector of one of the fields in the startup window and closed() it.