* ($family) and a key.
*
* Get a particular config value from the given category ($family)
- * and the $key from a cached storage in $a->config[$uid].
+ * and the $key from a cached storage in static::$config[$uid].
* $instore is only used by the set_config function
* to determine if the key already exists in the DB
* If a key is found in the DB but doesn't exist in