Method singleton

Lib/concurrent/interpreters/_crossinterp.py:42–59

(cls, kind, module, name='UNBOUND')

    @classonly
    def singleton(cls, kind, module, name='UNBOUND'):
        doc = cls.__doc__
        if doc:
            doc = doc.replace(
                'cross-interpreter container', kind,
            ).replace(
                'cross-interpreter', kind,
            )
        subclass = type(
            f'Unbound{kind.capitalize()}Item',
            (cls,),
            {
                "_MODULE": module,
                "_NAME": name,
                "__doc__": doc,
            },
        )
        return object.__new__(subclass)

    _MODULE = __name__
    _NAME = 'UNBOUND'