morass of closures for making decorators/descriptors

def _make_decorator(measuring_func):
    """morass of closures for making decorators/descriptors"""
    def _decorator(name = None, metric = call_default):
        def wrapper(func):

            name_ = name if name is not None else func.__module__ + '.' +func.__name__
            class instrument_decorator(object): # must be a class for descriptor magic to work
                @wraps(func)
                def __call__(self, *args, **kwargs):
                    return measuring_func(func(*args, **kwargs), name_, metric)

                def __get__(self, instance, class_):
                    name_ = name if name is not None else\
                        ".".join((class_.__module__, class_.__name__, func.__name__))
                    @wraps(func)
                    def wrapped_method(*args, **kwargs):
                        return measuring_func(func(instance, *args, **kwargs), name_, metric)
                    return wrapped_method
            return instrument_decorator()

        return wrapper
    return _decorator