Inspect redis cache

The API ref lists the methods below, but how can I return the complete list of memoized functions?

get_keys is always empty even when Redis shows there are keys in the console.

[5372] 24 Aug 13:56:11 - DB 0: 17 keys (17 volatile) in 32 slots HT.
[5372] 24 Aug 13:56:11 - 2 clients connected (0 slaves), 1200704 bytes in use

 'add',
 'app',
 'cache',
 'cached',
 'clear',
 'config',
 'delete',
 'delete_many',
 'delete_memoized',
 'delete_memoized_verhash',
 'get',
 'get_dict',
 'get_many',
 'init_app',
 'memoize',
 'set',
 'set_many',

https://pythonhosted.org/Flask-Caching/