be propagated up to the ``type.__new__`` call in order for the class to be
initialised correctly.
Failing to do so will result in a :exc:`DeprecationWarning` in Python 3.6,
- and a :exc:`RuntimeWarning` in the future.
+ and a :exc:`RuntimeError` in Python 3.8.
When using the default metaclass :class:`type`, or any metaclass that ultimately
calls ``type.__new__``, the following additional customisation steps are
direct references from methods to the implicit ``__class__`` closure
variable, the implicit ``__classcell__`` namespace entry must now be passed
up to ``type.__new__`` for initialisation. Failing to do so will result in
- a :exc:`DeprecationWarning` in 3.6 and a :exc:`RuntimeWarning` in the future.
+ a :exc:`DeprecationWarning` in Python 3.6 and a :exc:`RuntimeError` in
+ Python 3.8.
Changes in the C API
--------------------