Gets the value corresponding to the given key, creating it if
necessary. It first checks if the value already exists in the
#GCache, by using the key_equal_func function passed to
glib.cache.Cache.new_. If it does already exist it is returned, and its
reference count is increased by one. If the value does not currently
exist, if is created by calling the value_new_func. The key is
duplicated by calling key_dup_func and the duplicated key and value
are inserted into the #GCache.
Gets the value corresponding to the given key, creating it if necessary. It first checks if the value already exists in the #GCache, by using the key_equal_func function passed to glib.cache.Cache.new_. If it does already exist it is returned, and its reference count is increased by one. If the value does not currently exist, if is created by calling the value_new_func. The key is duplicated by calling key_dup_func and the duplicated key and value are inserted into the #GCache.