Python TkInter bind breaking -

i have simple gui uses key binds - this.

import tkinter, tkfiledialog  class foo(object):     def __init__(self, master):         master.bind('3', self.do_bar)         master.bind('9', self.load_new_config)          self.load_config()          if not self.conf:             self.load_new_config()         else:             self.load_data()      def load_config(self):         try:             self.conf = #get stuff known file         except failedtogetstuff:             self.conf = none      def load_new_config(self):         path = askopenfilename(initialdir='~')         self.conf = #get stuff file in path         self.load_data()      def load_data(self):         #get data self.conf, process , display      def do_bar(self):         #do stuff displayed data  if __name__ == "__main__"     root = tk()     foo(root)     root.mainloop() 

now, works fine when load_config() finds looking for. can use binds , after using '9' , loading new config, works.
problem is, if load_config() fails, self.conf gets set none , load_new_conf gets called __init__, binds no longer operational.

i figured out problem caused tkfiledialog.askopenfilename() being called within __init__. don't understand why happens , how around it.

this code works me:

import tkinter, tkfiledialog  class foo(object):     def __init__(self, master):         master.bind('<keypress-3>', self.do_bar)         master.bind('<keypress-9>', self.load_new_config)          self.load_config()          if not self.conf:             master.after(1, self.load_new_config)         else:             self.load_data()      def load_config(self):         try:             self.conf = none#get stuff known file         except failedtogetstuff:             self.conf = none      def load_new_config(self, e = 0):         path = tkfiledialog.askopenfilename(initialdir='~')         self.conf = none#get stuff file in path         self.load_data()      def load_data(self, e = 0):         pass         #get data self.conf, process , display      def do_bar(self, e = 0):         print 1         #do stuff displayed data  if __name__ == "__main__":     root = tkinter.tk()     foo(root)     root.mainloop()