public static function convertVoteInput (string $formula) : array
    {
        $ranking = explode('>', $formula);

        foreach ($ranking as &$rank_vote) :
            $rank_vote = explode('=', $rank_vote);

            // Del space at start and end
            foreach ($rank_vote as &$value) :
                $value = trim($value);
            endforeach;
        endforeach;

        return $ranking;
    }