ServiceScope.getServiceOrNull

static interface IPrime
{
    int getPrime();
}

static class PrimeThree : IPrime
{
    int getPrime()
    {
        return 3;
    }
}

auto services = new ServiceProvider([ServiceInfo.asTransient!(IPrime, PrimeThree)]);
auto service = services.defaultScope.getServiceOrNull!IPrime();
assert(service !is null);
assert(service.getPrime() == 3);