It would be useful to be able to clear a single item in the cache of a lru_cache decorated function.

Currently with:

@lru_cache
def foo(i):
  return i*2
foo(1)    # -> add 1 as key in the cache
foo(2)    # -> add 2 as key in the cache
foo.clear_cache() # -> this clears the whole cache
foo.clear_cache(1) # -> this would clear the cache entry for 1

Method with name clear() usually removes all content. It would be better to use different name: remove() or invalidate() (is there a precedence in other caches?).

I'm wary of adding too much complexity to the standard cache API, especially when it's something that isn't found in http://boltons.readthedocs.io/en/latest/cacheutils.html either.

I do think it could be a good idea to provide some "See Also" links to alternate caching libraries for folks that are looking for features that standard implementation doesn't provide.

I concur with Nick that the API needs to be relatively simple.

The availability of a fast ordered dictionary now makes it very easy for people to roll their own customizations.

FYI, here is a starting point for rolling your own variants.  The OrderedDict makes this effortless.  http://pastebin.com/LDwMwtp8