How do you import a heightmap file via c++ to create a large world partition landscape using Regions in 5.3?

Development Programming & Scripting
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I already have c++ code to import a heightmap file and create a world partition landscape. In 5.3 the new worldpartion sizes where added so you can create/import very large landscape such as size 15,301. When you have a very large size UE creates Regions as well as streaming proxies. How do I tell UE to create Regions in my c++ code?

My import code:

void UEditorLandscapeLibrary::ImportHeightmap(FString FilePath, FString LandscapeName,
                                              FString FileName, const int Width,
                                              const int Height, const int WorldPartitionGridSize)
{
	FilePath += + "\\" + FileName;

	int NewLandscape_QuadsPerSection;
	int NewLandscape_SectionsPerComponent;
	FIntPoint NewLandscape_ComponentCount;

	
	FLandscapeImportHelper::ChooseBestComponentSizeForImport(Width, Height, NewLandscape_QuadsPerSection, NewLandscape_SectionsPerComponent, NewLandscape_ComponentCount);

	const int32 ComponentCountX = NewLandscape_ComponentCount.X;
	const int32 ComponentCountY = NewLandscape_ComponentCount.Y;
	const int32 QuadsPerComponent = NewLandscape_SectionsPerComponent * NewLandscape_QuadsPerSection;
	const int32 SizeX = ComponentCountX * QuadsPerComponent + 1;
	const int32 SizeY = ComponentCountY * QuadsPerComponent + 1;

	
	ALandscape* Landscape = GEditor->GetEditorWorldContext().World()->SpawnActor<ALandscape>();
	Landscape->bCanHaveLayersContent = true;
	
	const auto ActualPath = FilePath.IsEmpty() ? Landscape->ReimportHeightmapFilePath : FilePath;
	if (ActualPath.IsEmpty())
		return;

	//Read png file to height array
	TArray<uint16> RawData;
	ReadHeightmapFile(RawData, *ActualPath, Width, Height);

	// Setup heightmap for landscape
	TMap<FGuid, TArray<uint16>> HeightmapDataPerLayers;
	TMap<FGuid, TArray<FLandscapeImportLayerInfo>> MaterialLayerDataPerLayer;

	// Generate LandscapeActor from heightmap
	HeightmapDataPerLayers.Add(FGuid(), RawData);
	MaterialLayerDataPerLayer.Add(FGuid(), TArray<FLandscapeImportLayerInfo>());

	Landscape->Import(FGuid::NewGuid(), 0, 0, SizeX - 1, SizeY - 1,
		NewLandscape_SectionsPerComponent, NewLandscape_QuadsPerSection, HeightmapDataPerLayers,
		*ActualPath, MaterialLayerDataPerLayer,  ELandscapeImportAlphamapType::Layered);

	ULandscapeInfo* LandscapeInfo = Landscape->GetLandscapeInfo();
	
	Landscape->SetActorLocation(FVector(0, 0, 100));
	Landscape->SetActorScale3D(FVector(100, 100, 100));
	Landscape->SetActorLabel(LandscapeName);
	LandscapeInfo->UpdateLayerInfoMap(Landscape);
	UE_LOG(LogStreaming, Warning, TEXT("GridSize: %d"), WorldPartitionGridSize);
	if (WorldPartitionGridSize > 0)
	{
		//Setup World partition streaming proxies
		GEditor->GetEditorWorldContext().World()->GetSubsystem<ULandscapeSubsystem>()->ChangeGridSize(LandscapeInfo, WorldPartitionGridSize);
	}
	
}

So this line

  //Setup World partition streaming proxies
		GEditor->GetEditorWorldContext().World()->GetSubsystem<ULandscapeSubsystem>()->ChangeGridSize(LandscapeInfo, WorldPartitionGridSize);

This allows me to easily specify the landscape should be a world partition and import it with streaming proxies. Is there a one liner like this where I can specify region and number of regions to make UE import the landscape using Regions?