Just like functools.lru_cache, but creates a new cache for each instance - which is more useful for methods.

instance_cache.py

def instance_method_lru_cache(*cache_args, **cache_kwargs):
    '''
    Just like functools.lru_cache, but a new cache is created for each instance
    of the class that owns the method this is applied to.
    '''
    def cache_decorator(func):
        @wraps(func)
        def cache_factory(self, *args, **kwargs):
            # Wrap the function in a cache by calling the decorator
            instance_cache = lru_cache(*cache_args, **cache_kwargs)(func)
            # Bind the decorated function to the instance to make it a method
            instance_cache = instance_cache.__get__(self, self.__class__)
            setattr(self, func.__name__, instance_cache)
            # Call the instance cache now. Next time the method is called, the
            # call will go directly to the instance cache and not via this
            # decorator.
            return instance_cache(*args, **kwargs)
        return cache_factory
    return cache_decorator