The Tweener is a powerfull tool to interpolate between different states in parameters over time. This can be archived in an absolute way, defining a time in which the interpolation needs to be done
op('tweener').AbsoluteTween( target_parameter, target_value, time_in_seconds )
Or in a relative way, defining a speed in difference per seconds.
op('tweener').RelativeTween( target_parameter, target_value, difference_per_second )
You can also add a curve argument ("s", "lin", "sqr"...´) and a delay argument to delay the execution of the tween in seconds.
To stop a specific tween, call the StopFade(target_parameter) or, top stop all tweens, the StopAllFades() method.