How to use the patchy.core.PatchClass function in patchy

def patchy(target, source=None):
    """ If source is not supplied, auto updates cannot be applied """
    if isinstance(target, str):
        target = resolve(target)
    if isinstance(source, str):
        source = resolve(source)
    if isinstance(target, ModuleType):
        return PatchModule(target, source)
    elif isinstance(target, type) and source:
        return PatchClass(target, source)

def cls(self, target, source=None):
        if isinstance(target, str):
            target = resolve(target, package=self.target)
        if self.source and source is None:
            with suppress(ImportError):
                source_str = '{mod}.{cls}'.format(
                    mod=target.__module__.replace('.', self.module_sep),
                    cls=target.__name__)
                source = resolve(source_str, package=self.source)
            if not source:
                with suppress(AttributeError):
                    source = getattr(self.source, target.__name__)
        elif isinstance(source, str):
            source = resolve(source, package=self.source)
        if isinstance(target, type):
            return PatchClass(target, source)
        raise TypeError('Must be a valid class or class name')