gtk3 - Python Gtk 3 window is not defined, class instancing confusion -

i starting python , utterly confused how object creation works. trying create user interface gtk. here example of problem having:

from gi.repository import gtk   def button_clicked(self, button):     self.button_label = button.get_label()     if self.button_label == "login":         window.quit()         window2.start()  class loginwindow(gtk.window):     def __init__(self):         gtk.window.__init__(self, title="amok cloud")         self.connect("delete-event", gtk.main_quit)         self.set_position(position = gtk.windowposition.center)          # button         self.loginbutton = gtk.button(label="login")         self.loginbutton.connect("clicked", button_clicked(self, self.loginbutton))         self.add(self.loginbutton)          self.show_all()         gtk.main()      def quit(self):         self.close()         gtk.main_quit()  class mainwindow(gtk.window):     def __init__(self):         gtk.window.__init__(self, title="amok cloud")         self.connect("delete-event", gtk.main_quit)         self.set_position(position=gtk.windowposition.center)      def start(self):         self.show_all()         gtk.main()  window = loginwindow() window2 = mainwindow() 

error comes nameerror: name 'window' not defined though did define window. don't understand. if can explain mean world me. in advance.

edit: guys works fine now, took gtk.main() out of both classes , added button_clicked method inside loginwindow() class , works charm. assumed needed gtk.main() every window open.

it because starting main loop (gtk.main()) inside of loginwindow.__init__(). means window = loginwindow() line doesn't finish executing until after login window closed. should take gtk.main() outside of __init__ method, , move last line in file. mentioned pm 2ring in comments, don't need call gtk.main() twice. take out in mainwindow.start() because 1 added last line in file takes care of that. mentioned pm, connect() calls function when event happens. when give button_clicked(...), function called , telling connect() call whatever returned, none. if want special arguments, use lambda, aren't changing (those default arguments anyway), can this:

self.connect("clicked", button_clicked) 

i suggest instead of making button_clicked separate function, make static method of class. placing inside class, @staticmethod above def line. way, makes sense take self argument, don't need 2 parameters account same window.