gtk:radio-menu-item-new-with-mnemonic (group label)

group -- a list of gtk:radio-menu-item widgets for the radio group to which the radio menu item is to be attached or nil
label -- a string for the text of the radio menu item, with an underscore in front of the mnemonic character

The new gtk:radio-menu-item widget.

Creates a new radio menu item containing a label. The label will be created using the gtk:label-new-with-mnemonic function, so underscores in the label indicate the mnemonic for the menu item.