A CacheSet is used to collect and maintain a series of caches. In
SQLObject, there is one CacheSet per connection, and one Cache
in the CacheSet for each class, since IDs are not unique across
classes. It contains methods similar to Cache, but that take
a cls argument.
The CacheSet class is accessible via the
Abstract classes can override this to customize issubclass().
This is invoked early on by abc.ABCMeta.__subclasscheck__().
It should return True, False or NotImplemented. If it returns
NotImplemented, the normal algorithm is used. Otherwise, it
overrides the normal algorithm (and the outcome is cached).
__sizeof__() -> int
size of object in memory, in bytes
Move all objects in the cls (or if not given, then in all
classes) to the weakref dictionary, where they can be
Returns all instances in the cache for the given class or all
for more information.