Python 3.9 is now generally available.

google.appengine.api.memcache.get_multi

Looks up multiple keys from memcache in one operation.

This is the recommended way to do bulk loads.

keys List of keys to look up. Keys may be strings or tuples of (hash_value, string). Google App Engine does the sharding and hashing automatically, though, so the hash value is ignored. To memcache, keys are just series of bytes, and not in any particular encoding.
key_prefix Prefix to prepend to all keys when talking to the server; not included in the returned dictionary.
namespace a string specifying an optional namespace to use in the request.
for_cas If True, request and store CAS ids on the client.

A dictionary of the keys and values that were present in memcache. Even if the key_prefix was specified, that key_prefix won't be on the keys in the returned dictionary.