@contextlib.contextmanager
    def decoration_helper(self, patched, args, keywargs):
        extra_args = []
        entered_patchers = []
        patching = None

        exc_info = tuple()
        try:
            for patching in patched.patchings:
                arg = patching.__enter__()
                entered_patchers.append(patching)
                if patching.attribute_name is not None:
                    keywargs.update(arg)
                elif patching.new is DEFAULT:
                    extra_args.append(arg)

            args += tuple(extra_args)
            yield (args, keywargs)
        except:
            if (patching not in entered_patchers and
                _is_started(patching)):
                # the patcher may have been started, but an exception
                # raised whilst entering one of its additional_patchers
                entered_patchers.append(patching)
            # Pass the exception to __exit__
            exc_info = sys.exc_info()
            # re-raise the exception
            raise
        finally:
            for patching in reversed(entered_patchers):
                patching.__exit__(*exc_info)


    def decorate_callable(self, func):
        if hasattr(func, 'patchings'):
            func.patchings.append(self)
            return func

        @wraps(func)
        def patched(*args, **keywargs):
            with self.decoration_helper(patched,
                                        args,
                                        keywargs) as (newargs, newkeywargs):
                return func(*newargs, **newkeywargs)

        patched.patchings = [self]
        return patched


    def decorate_async_callable(self, func):
        '''This is same as decorate_callable except patched is a coroutine'''
        if hasattr(func, 'patchings'):
            func.patchings.append(self)
            return func

        @wraps(func)
        async def patched(*args, **keywargs):
            with self.decoration_helper(patched,
                                        args,
                                        keywargs) as (newargs, newkeywargs):
                return await func(*newargs, **newkeywargs)

        patched.patchings = [self]
        return patched