The pre_move_validation() method also calls another method called update_game_statistics() on successfully recording a move (see 4.06—model.py):

    def update_game_statistics(self, piece, dest, start_pos, end_pos):
        if piece.color == 'black':
            self.fullmove_number += 1
        self.halfmove_clock += 1
        abbr = piece.name
        if abbr == 'pawn':
            abbr = ''
            self.halfmove_clock = 0
        if dest is None:
            move_text = abbr + end_pos.lower()
        else:
            move_text = abbr + 'x' + end_pos.lower()
            self.halfmove_clock = 0
        self.history.append(move_text)

Congratulations, our chess game is now functional!

Let's complete the iteration by binding the File | New Game menu item to start a new game. Earlier, we defined the start_new_game() method. Now, it's simply a matter of calling it from the on_new_game_menu_clicked() method, as follows (4.06—view.py):

def on_new_game_menu_clicked(self):
  self.start_new_game()