Hi @delizade,
thank you for reaching out to us. There are two problems with your code:
You are using C4DAtom.GetClone() and GeListNode.InsertUnder() to add and clone a take. You should instead use TakeData.AddTake() which also provides a cloneFrom argument (Link for AddTake).
You are cloning and inserting the main take, which leads in Python to hiccups. Because even when you do it correctly, like discussed in this thread via AddTake, it will insert a second "main take" into a document. I.e., one which has no "inherit from parent" and "default cemara/rendersettings" icons.
According to one our devs, No. 2 seems to be a Python bug and not a limitation, we will investigate that. For now you would have to clone the two child takes under the main take manually in Python (and add a parent take beforehand if you want this structure). Because otherwise you will end up with two "root/main" takes in your document, confusing Cinema 4D ;)
Cheers,
Ferdinand