public function getAvatars(array $accounts)
    {
        $ids = [];
        foreach ($accounts as $account) {
            if ($account instanceof Account) {
                $ids[] = $account->getId();
            } else {
                $ids[] = $account;
            }
        }

        $response = $this->client->sendRequest(
            $this->getBase() . '/Avatar',
            'POST',
            $ids
        );
        if (!is_array($response)) {
            throw new UnexpectedValueException('Array expected, but got ' . gettype($response));
        }

        $result = [];
        /** @var array $response */
        foreach ($response as $item) {
            try {
                $result[] = new FileStruct($item);
            } catch (\InvalidArgumentException $e) {
                throw new UnexpectedValueException($e->getMessage(), $e->getCode(), $e);
            }
        }

        return $result;
    }