Add a wall collision reward

def reward_wall(self):
        """
        Add a wall collision reward
        """
        if not 'wall' in self.mode:
            return
        mode = self.mode['wall']
        if mode and mode and self.__test_cond(mode):
            self.logger.debug("Wall {x}/{y}'".format(x=self.bumped_x, y=self.bumped_y))
            self.player.stats['reward'] += mode['reward']

            self.player.game_over = self.player.game_over or mode['terminal']