* bpo-32492: 2.5x speed up in namedtuple attribute access using C fast path
* Add News entry
* fixup! bpo-32492: 2.5x speed up in namedtuple attribute access using C fast path
* Check for tuple in the __get__ of the new descriptor and don't cache the descriptor itself
* Don't inherit from property. Implement GC methods to handle __doc__
* Add a test for the docstring substitution in descriptors
* Update NEWS entry to reflect time against 3.7 branch
* Simplify implementation with argument clinic, better error messages, only __new__
* Use positional-only parameters for the __new__
* Use PyTuple_GET_SIZE and PyTuple_GET_ITEM to tighter the implementation of tuplegetterdescr_get
* Implement __set__ to make tuplegetter a data descriptor
* Use Py_INCREF now that we inline PyTuple_GetItem
* Apply the valid_index() function, saving one test
* Move Py_None test out of the critical path.