>>> help(list[int])
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/serhiy/py/cpython/Lib/_sitebuiltins.py", line 103, in __call__
    return pydoc.help(*args, **kwds)
  File "/home/serhiy/py/cpython/Lib/pydoc.py", line 1905, in __call__
    self.help(request)
  File "/home/serhiy/py/cpython/Lib/pydoc.py", line 1964, in help
    else: doc(request, 'Help on %s:', output=self._output)
  File "/home/serhiy/py/cpython/Lib/pydoc.py", line 1684, in doc
    pager(render_doc(thing, title, forceload))
  File "/home/serhiy/py/cpython/Lib/pydoc.py", line 1677, in render_doc
    return title % desc + '\n\n' + renderer.document(object, name)
  File "/home/serhiy/py/cpython/Lib/pydoc.py", line 381, in document
    if inspect.isclass(object): return self.docclass(*args)
  File "/home/serhiy/py/cpython/Lib/pydoc.py", line 1251, in docclass
    (str(cls.__name__) for cls in type.__subclasses__(object)
TypeError: descriptor '__subclasses__' for 'type' objects doesn't apply to a 'types.GenericAlias' object