How do I create and use keyboard shortcuts in a Gtk app that I am developing?

Here's some bits of code from one of my Python + Gtk apps, further extended according to the comments to this answer:

self.my_accelerators = Gtk.AccelGroup()
self.entry = Gtk.builder.get_object("entry1")
self.add_accelerator(self.entry, "<Control>b", signal="backspace")
...

def add_accelerator(self, widget, accelerator, signal="activate"):
    """Adds a keyboard shortcut"""
    if accelerator is not None:
        #if DEBUG:
            #print accelerator, widget.get_tooltip_text()
        key, mod = Gtk.accelerator_parse(accelerator)
        widget.add_accelerator(signal, self.my_accelerators, key, mod, Gtk.AccelFlags.VISIBLE)

Here is the code that finally worked. As it depends highly on my development environment Quickly + Glade + Python + Gtk, I make it an independent answer. Bryce's answer helped a lot, and so did my exchanges with aking1012.

The actual code, in a text editor:

# Accelerators
self.my_accelerators = Gtk.AccelGroup()
self.window = self.builder.get_object("discvur_window")
self.window.add_accel_group(self.my_accelerators)
self.entry = self.builder.get_object("entry1")
self.add_accelerator(self.entry, "<Control>b", signal="backspace")

…

def add_accelerator(self, widget, accelerator, signal="activate"):
    """Adds a keyboard shortcut"""
    if accelerator is not None:
        #if DEBUG:
            #print accelerator, widget.get_tooltip_text()
        key, mod = Gtk.accelerator_parse(accelerator)
        widget.add_accelerator(signal, self.my_accelerators, key, mod, Gtk.AccelFlags.VISIBLE)
        print "The accelerator is well added with the signal " + signal

def on_erasing(self, widget):
    print "It works."

In Glade, I created a GtkEntry called "entry1" in my window called "discvur_window". In the 'Signals' tab, I gave the signal "backspace" a handler called "on_erasing".

Now, hitting Backspace or Ctrl+B makes the terminal print "It works.".

I've repackaged the given answers in this thread into a standalone example:

#!/usr/bin/env python2

import signal

from gi.repository import Gtk

def bind_accelerator(accelerators, widget, accelerator, signal='clicked'):
    key, mod = Gtk.accelerator_parse(accelerator)
    widget.add_accelerator(signal, accelerators, key, mod, Gtk.AccelFlags.VISIBLE)

def on_recompute_base_encryption_key_hash(widget):
    print 'Thinking... (This could take forever)'

def main():

    if 'gtk':
        window = Gtk.Window()
        window.connect("delete-event", Gtk.main_quit)

        if 'accelerator-demo':
            # Accelerators
            accelerators = Gtk.AccelGroup()
            window.add_accel_group(accelerators)

            # Widget
            target_widget = Gtk.Button('Recompute Base Encryption Key Hash')
            target_widget.connect('clicked', on_recompute_base_encryption_key_hash)
            window.add(target_widget)

            # Bind
            bind_accelerator(accelerators, target_widget, '<Control>b')

        window.show_all()
        signal.signal(signal.SIGINT, signal.SIG_DFL)
        Gtk.main()

if __name__ == '__main__':
    main()

Also available as a gist: https://gist.github.com/thorsummoner/230bed5bbd3380bd5949

Note: The default signal is clicked, not activate because Applications should never connect to the ::activate signal, but use the Gtk.Button ::clicked signal.