set o [new Observable]
Observable class. Instead, other classes (for example, ArchiveStream, ArchiveSession/Play, ArchiveSession/Record) derive from this class.
$o attach_observer $observerAppend a new observer to the list of observers associated with this object. The
notify_observers method uses this list to figure out which observers to notify.
Returns: Nothing. detach_observer:
$o detach_observer $observerRemove an existing observer from the list of observers associated with this object.
Returns: Nothing. notify_observers:
$o notify_observers $event ...Notify all observers associated with this object (via the
attach_observer method) about a change in the observable entity's status. notify_observers takes the name of the event followed by a variable number of arguments as input and passes them on to the update method of each of the observers.
Returns: Nothing.