How to use the xpra.util.nn function in xpra

keycodes=[]
    for i in range(0, 2**8):
        entries = keymap.get_entries_for_keycode(i)
        log("%s.get_entries_for_keycode(%s)=%s", keymap, i, entries)
        if not entries:
            continue
        if is_gtk3():
            found, keys, keyvals = entries
            if not found:
                continue
            for i in range(len(keys)):
                key = keys[i]
                keyval = keyvals[i]
                name = gdk.keyval_name(keyval)
                if name not in ignore_keys:
                    keycodes.append((nn(keyval), nn(name), nn(key.keycode), nn(key.group), nn(key.level)))
        else:
            #gtk2:
            for keyval, keycode, group, level in entries:
                #assert keycode==i
                name = gdk.keyval_name(keyval)
                #ugly workaround for "period" key on win32 (see ticket 588)
                #which is reported as "period" instead of "KP_Decimal",
                #despite being on the numeric keypad just like all the other KP_* keys...
                if name=="period" and keyval==46 and keycode==110:
                    name = "KP_Decimal"
                elif name=="dead_tilde" and keyval==65107 and keycode==50:
                    name = "asciitilde"
                elif name=="dead_grave" and keyval==65104 and keycode==55:
                    name = "grave"
                if name not in ignore_keys:
                    keycodes.append((nn(keyval), nn(name), nn(keycode), nn(group), nn(level)))

def parse_key_event(self, event, pressed):
        key_event = GTKKeyEvent()
        key_event.modifiers = self._client.mask_to_names(event.state)
        key_event.keyname = nn(gdk.keyval_name(event.keyval))
        key_event.keyval = nn(event.keyval)
        key_event.keycode = event.hardware_keycode
        key_event.group = event.group
        key_event.string = nn(event.string)
        key_event.pressed = pressed
        keylog("parse_key_event(%s, %s)=%s", event, pressed, key_event)
        return key_event

def parse_key_event(self, event, pressed):
        key_event = GTKKeyEvent()
        key_event.modifiers = self._client.mask_to_names(event.state)
        key_event.keyname = nn(gdk.keyval_name(event.keyval))
        key_event.keyval = nn(event.keyval)
        key_event.keycode = event.hardware_keycode
        key_event.group = event.group
        key_event.string = nn(event.string)
        key_event.pressed = pressed
        return key_event

def send_layout(self):
        keylog("send_layout()")
        self.send("layout-changed", nn(self.keyboard_helper.xkbmap_layout), nn(self.keyboard_helper.xkbmap_variant))

def get_keymap_properties(self):
        props = {}
        for x in ["xkbmap_print", "xkbmap_query", "xkbmap_mod_meanings",
              "xkbmap_mod_managed", "xkbmap_mod_pointermissing", "xkbmap_keycodes", "xkbmap_x11_keycodes"]:
            props[x] = nn(getattr(self, x))
        return  props