[Tutor] Creating menu shortcut key bindings

[Phil]

I've fooled around with this for several hours including extensive 
searching of the Internet.

What I have is a file menu with open and exit options that I've created 
with pygubu, which works perfectly. Now I'm trying to add a shortcut key 
(ctl + o) to open a file.

The code under 'Get a reference to the "Open" menu item widget' and 
'Bind the shortcut key to the menu item' does not produce an error. So I 
presume that the code under "Set the accelerator property of the menu 
item to 'Control+O'" is the problem.

My AI friend has suggested several options but they all result in an 
'unknown option' error message.

Can anyone see where I've gone astray?

     def __init__(self, master=None):
         self.builder = builder = pygubu.Builder()
         builder.add_resource_path(PROJECT_PATH)
         builder.add_from_file(PROJECT_UI)

         # Main widget
         self.mainwindow = builder.get_object("Toplevel1", master)

         # Main menu

         _main_menu = builder.get_object("Menu1", self.mainwindow)
         self.mainwindow.configure(menu=_main_menu)
         builder.connect_callbacks(self)

         # Get a reference to the "Open" menu item widget
         open_menu_item = builder.get_object("mnu_open", _main_menu) # 
no error here

         # Set the accelerator property of the menu item to 'Control+O' 
# option problems here
         #open_menu_item['underline'] = 0#'Control+O'
         #open_menu_item['label'] = 'Open\tCtrl+O'
         #open_menu_item['<Control-o>']#accelerator'] = 'Ctrl+O'

         # Bind the shortcut key to the menu item
         self.mainwindow.bind('<Control-o>', lambda event: 
open_menu_item.invoke()) # no error here

-- 
Regards,
Phil