use AppBaseServiceAccountService;
use AppBaseServiceBaseService;


class MainService extends BaseService
{
/**
 * @param AccountService $accountService
 */
public function __construct(AccountService $accountService)
{
    parent::__construct();
    $this->accountService = $accountService;
}

this->accountService->getMyFunction();

class BaseService
{
    /** @var ContainerInterface  */
    var $container;
    var $em;

public function __construct(ContainerInterface $container, EntityManagerInterface $em)
{
    $this->container = $container;
    $this->em = $em;
}