code: def populate_keys_tree(self):
          
          for group in HOTKEYS:
              parent = self.store.append(None, [None, group['label'], None, None])
              for item in group['keys']:
                  if item['key'] == "show-hide" or item['key'] == "show-focus":
                      accel = self.settings.keybindingsGlobal.get_string(item['key'])
                  else:
                      accel = self.settings.keybindingsLocal.get_string(item['key'])
                  gsettings_path = item['key']
                  keycode, mask = Gtk.accelerator_parse(accel)
                  keylabel = Gtk.accelerator_get_label(keycode, mask)
                  self.store.append(parent, [gsettings_path, item['label'], keylabel, accel])
          self.get_widget('treeview-keys').expand_all()
docs: Reads the HOTKEYS global variable and insert all data in
          the TreeStore used by the preferences window treeview.