Asyncio cache supporting multiple backends (memory, redis and
memcached).

This library aims for simplicity over specialization. All caches contain
the same minimum interface which consists on the following functions:

 - add: Only adds key/value if key does not exist.
 - get: Retrieve value identified by key.
 - set: Sets key/value.
 - multi_get: Retrieves multiple key/values.
 - multi_set: Sets multiple key/values.
 - exists: Returns True if key exists False otherwise.
 - increment: Increment the value stored in the given key.
 - delete: Deletes key and returns number of deleted items.
 - clear: Clears the items stored.
 - raw: Executes the specified command using the underlying client.

See example of usage here: https://github.com/aio-libs/aiocache
