public static function getBalanceList()
    {
        $balances = array();
        foreach (self::_getAllBalances() as $value) {
            $value = (array)$value;
            unset($value['result']);
            unset($value['error']);
            $balance = new Balance(array("prepaid_balance" => $value['prepaid_balance_amount'], "customer_id" => $value["customer_id"]));
            $balances[$value['customer_id']] = $balance;
        }
        return $balances;
    }