I'm not sure if you need to go into so much detail on metaclasses here. I think it's enough to say that this method gets called when an instance of any class derived from this metaclass is created. Put another way, I would take out all discussion of `type` and `type.__call__`.

I say this not because it should be clear how metaclasses work, but because it is confusing how they work, and a short description like the one here only serves to further muddy things. To understand metaclasses, a full document is required. So write this docstring simply describing it's purpose and when this function will get called (the phrase "in order to do all of the add_to_network stuff automatically after __init__" is good).