I looked into cache contents and I see that all objects are wrapped by keyedcache.CacheWrapper object and then pickled by Django.core.cache.
For example the integer 5 is saved like
# by keyedcache '\x80\x02ckeyedcache\nCacheWrapper\nq\x01)\x81q\x02}q\x03(U\tinprocessq\x04\x89U\x03valq\x05Nub.' # directly by Django cache '\x80\x02K\x05.'
There are seen unimportant identifiers ['keyedcache', 'CacheWrapper', 'inprocess', 'val'] in every value.
I wrote a documantation to unclear parts and now I think that keyedcache can be easy modified to be more transparent if a known value is cached and will be complicated only if a Function Caching "in process" is used.