Fails to build with target Gtk-4.0

[tallero]

➜  pgi-docgen git:(master) ./tools/build-devhelp.sh Gtk-4.0                                                                                                       
Traceback (most recent call last):
  File "/home/user/Projects/pgi-docgen/./pgi-docgen", line 14, in <module>
    sys.exit(main(sys.argv))
  File "/home/user/Projects/pgi-docgen/pgidocgen/main.py", line 29, in main
    return args.func(args)
  File "/home/user/Projects/pgi-docgen/pgidocgen/create.py", line 61, in main
    gen.write(args.target)
  File "/home/user/Projects/pgi-docgen/pgidocgen/gen/module.py", line 129, in write
    mods = get_to_write(dir_, self._namespace, self._version)
  File "/home/user/Projects/pgi-docgen/pgidocgen/gen/module.py", line 122, in get_to_write
    ns = get_namespace(namespace, version)
  File "/home/user/Projects/pgi-docgen/pgidocgen/namespace.py", line 50, in get_namespace
    getattr(ns, k)
  File "/home/user/Projects/pgi-docgen/pgidocgen/util.py", line 605, in __get__
    obj.__dict__[self.__name__] = result = self.fget(obj)
  File "/home/user/Projects/pgi-docgen/pgidocgen/namespace.py", line 171, in shadow_map
    self._ensure_types()
  File "/home/user/Projects/pgi-docgen/pgidocgen/namespace.py", line 160, in _ensure_types
    _parse_types(dom, self.import_module(), self.namespace)
  File "/home/user/Projects/pgi-docgen/pgidocgen/namespace.py", line 186, in import_module
    to_load = list(reversed(self.all_dependencies))
  File "/home/user/Projects/pgi-docgen/pgidocgen/util.py", line 605, in __get__
    obj.__dict__[self.__name__] = result = self.fget(obj)
  File "/home/user/Projects/pgi-docgen/pgidocgen/namespace.py", line 274, in all_dependencies
    sub_ns = get_namespace(*key)
  File "/home/user/Projects/pgi-docgen/pgidocgen/namespace.py", line 50, in get_namespace
    getattr(ns, k)
  File "/home/user/Projects/pgi-docgen/pgidocgen/util.py", line 605, in __get__
    obj.__dict__[self.__name__] = result = self.fget(obj)
  File "/home/user/Projects/pgi-docgen/pgidocgen/namespace.py", line 171, in shadow_map
    self._ensure_types()
  File "/home/user/Projects/pgi-docgen/pgidocgen/namespace.py", line 160, in _ensure_types
    _parse_types(dom, self.import_module(), self.namespace)
  File "/home/user/Projects/pgi-docgen/pgidocgen/namespace.py", line 186, in import_module
    to_load = list(reversed(self.all_dependencies))
  File "/home/user/Projects/pgi-docgen/pgidocgen/util.py", line 605, in __get__
    obj.__dict__[self.__name__] = result = self.fget(obj)
  File "/home/user/Projects/pgi-docgen/pgidocgen/namespace.py", line 274, in all_dependencies
    sub_ns = get_namespace(*key)
  File "/home/user/Projects/pgi-docgen/pgidocgen/namespace.py", line 50, in get_namespace
    getattr(ns, k)
  File "/home/user/Projects/pgi-docgen/pgidocgen/util.py", line 605, in __get__
    obj.__dict__[self.__name__] = result = self.fget(obj)
  File "/home/user/Projects/pgi-docgen/pgidocgen/namespace.py", line 171, in shadow_map
    self._ensure_types()
  File "/home/user/Projects/pgi-docgen/pgidocgen/namespace.py", line 160, in _ensure_types
    _parse_types(dom, self.import_module(), self.namespace)
  File "/home/user/Projects/pgi-docgen/pgidocgen/namespace.py", line 190, in import_module
    module = util.import_namespace(namespace, version)
  File "/home/user/Projects/pgi-docgen/pgidocgen/util.py", line 563, in import_namespace
    __import__("gi.repository." + namespace).repository, namespace)
  File "<frozen importlib._bootstrap>", line 1007, in _find_and_load
  File "<frozen importlib._bootstrap>", line 986, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 664, in _load_unlocked
  File "<frozen importlib._bootstrap>", line 627, in _load_backward_compatible
  File "/usr/lib/python3.9/site-packages/pgi/importer.py", line 182, in load_module
    proxy = overrides.load_overrides(introspection_module)
  File "/usr/lib/python3.9/site-packages/pgi/overrides/__init__.py", line 121, in load_overrides
    override_mod = importlib.import_module(override_package_name)
  File "/usr/lib/python3.9/importlib/__init__.py", line 127, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "/usr/lib/python3.9/site-packages/pgi/overrides/Gdk.py", line 44, in <module>
    class Color(Gdk.Color):
  File "/usr/lib/python3.9/site-packages/pgi/module.py", line 83, in __getattr__
    raise AttributeError("%r module has not attribute %r" %
AttributeError: 'Gdk' module has not attribute 'Color'