public function getSortedPurses()
    {
        $purses = $this->purses;
        if (empty($purses)) {
            return $purses;
        }

        $getOrder = function ($currency) {
            $order = ['usd' => 0, 'eur' => 1];

            return $order[$currency] ?? 100;
        };

        usort($purses, function ($a, $b) use ($getOrder) {
            return $getOrder($a->currency) <=> $getOrder($b->currency);
        });

        return $purses;
    }