public function move($move)
    {
        $last_move = $this->getLastMoveIndex();
        
        if (is_array($last_move) && array_shift($last_move) === false)
        {
            throw new RockPaperScissorsSpockLizardException('Cannot set another move until the previous move has been played');
        }
        
        if (empty($move)) {
            throw new RockPaperScissorsSpockLizardException('Move cannot be empty');
        }
        
        $this->moves[] = [$move => false];
        
        return $this;
    }