pick a move at random from the list of moves

def _next_move_direction(self):
        """
        pick a move at random from the list of moves
        """
        nmoves = len(self.moves)
        move = np.random.randint(1, nmoves+1)
        while self.prev_move == (move + 3) % nmoves:
            move = np.random.randint(1, nmoves+1)
        self.prev_move = move
        return np.array(self.moves[move])