Feature             ,Cython 0.29        ,Cython 3.0                
``int``,Any Python object,Exact Python ``int`` (``language_level=3`` only)
``float``,,C ``double``
"Builtin type  e.g. ``dict``, ``list`` ",,"Exact type (no  subclasses), not ``None``"
Extension type defined in Cython ,,"Specified type or a  subclasses, not ``None``"
"``cython.int``,  ``cython.long``,  etc. ",,Equivalent C numeric type
``typing.Optional[any_type]``,Not supported,"Specified type (which  must be a Python object), allows ``None``"
``typing.List[any_type]``  (and similar) ,Not supported,"Exact ``list``, with the element type ignored currently "
``typing.ClassVar[...]`` ,Not supported,Python-object class variable (when used in a class definition)