google.appengine.api.memcache.replace_multi

Replace multiple keys' values, failing if the items aren't in memcache.

google.appengine.api.memcache.replace_multi(
    mapping,
    time=0,
    key_prefix='',
    min_compress_len=0,
    namespace=None
)

mapping Dictionary of keys to values.
time Optional expiration time, either relative number of seconds from current time (up to 1 month), or an absolute Unix epoch time. By default, items never expire, though items may be evicted due to memory pressure. Float values will be rounded up to the nearest whole second.
key_prefix Prefix for to prepend to all keys.
min_compress_len Unimplemented compatibility option.
namespace a string specifying an optional namespace to use in the request.

A list of keys whose values were NOT set because they already existed in memcache. On total success, this list should be empty.