Using Dynamo to place multiple instances in a Revit Project

and this is a picture of the Dynamo definition:

The code works with no errors.
My doubt is about the workflow, probably I am missing something here. The objects you see in the previous picture are real revit family instances, I can even schedule them! but when I try to generate the next set of object they all disappear, as if they were still linked to the dynamo definition that created them (they surely are).

I just want to tell Dynamo: “OK, those family instances are just fine! let’s move on and create more without deleting them!”

Thanks again to everybody, have a nice sunday!