Contrary to what the article says, PyVarObject is still PyObject at the same time and PyVarObjects have nothing to do with mutability (certainly, it's trivialy

Contrary to what the article says, PyVarObject is still PyObject at the same time and PyVarObjects have nothing to do with mutability (certainly, it's trivialy obvious that not all PyVarObjects are mutable as immutable tuples are PyVarObjects, while mutable lists are not) The thing that is handled by PyVarObject are types whose instances can differ in their size, with tuple and bytes objects being probably most common cases when it is used.