private function balanceHandler(array $json)
    {
        $balances = [];
        foreach ($json as $item) {
            $asset = $item->a;
            $available = $item->f;
            $onOrder = $item->l;
            $balances[$asset] = [
                "available" => $available,
                "onOrder" => $onOrder,
            ];
        }
        return $balances;
    }