EQS Generator c++ returning result

I am creating a custom eqs generator, but I have trouble figuring out how to return the value for the blackboard to work with. This is the code I currently have in the generator.

void UFindUnequippedFirearmGenerator::GenerateItems(FEnvQueryInstance& QueryInstance) const
{
AActor* aiPawn = Cast((QueryInstance.Owner).Get());
for (TActorIterator ActorItr(GetWorld()); ActorItr; ++ActorItr)
{
if ((ActorItr->GetActorLocation() - aiPawn->GetActorLocation()).Size() <= _range)
{
AFirearm *desiredFirearm = *ActorItr;
QueryInstance.AddItemData(*ActorItr);
return;

	}		
}

}

When I try to compile this Unreal tells me: ‘FValueType’: is not a member of ‘UFindUnequippedFirearmGenerator’