How to use the cachetools.keys._HashedTuple function in cachetools

def __radd__(self, other, add=tuple.__add__):
        return _HashedTuple(add(other, self))

def hashkey(*args, **kwargs):
    """Return a cache key for the specified hashable arguments."""

    if kwargs:
        return _HashedTuple(args + sum(sorted(kwargs.items()), _kwmark))
    else:
        return _HashedTuple(args)

def hashkey(*args, **kwargs):
    """Return a cache key for the specified hashable arguments."""

    if kwargs:
        return _HashedTuple(args + sum(sorted(kwargs.items()), _kwmark))
    else:
        return _HashedTuple(args)

def __add__(self, other, add=tuple.__add__):
        return _HashedTuple(add(self, other))

self.__hashvalue = hashvalue = hash(self)
        return hashvalue

    def __add__(self, other, add=tuple.__add__):
        return _HashedTuple(add(self, other))

    def __radd__(self, other, add=tuple.__add__):
        return _HashedTuple(add(other, self))

    def __getstate__(self):
        return {}


# used for separating keyword arguments; we do not use an object
# instance here so identity is preserved when pickling/unpickling
_kwmark = (_HashedTuple,)


def hashkey(*args, **kwargs):
    """Return a cache key for the specified hashable arguments."""

    if kwargs:
        return _HashedTuple(args + sum(sorted(kwargs.items()), _kwmark))
    else:
        return _HashedTuple(args)


def typedkey(*args, **kwargs):
    """Return a typed cache key for the specified hashable arguments."""

    key = hashkey(*args, **kwargs)
    key += tuple(type(v) for v in args)