Optional number of seconds to make deleted items 'locked'
for 'add' operations. Value can be a delta from current time (up to
1 month), or an absolute Unix epoch time. Defaults to 0, which means
items can be immediately added. With or without this option,
a 'set' operation will always work. Float values will be rounded up to
the nearest whole second.
Prefix to put on all keys when sending specified
keys to memcache. See docs for get_multi() and set_multi().
a string specifying an optional namespace to use in
True if all operations completed successfully. False if one
or more failed to complete.