The script attached to this event fires when an item is used. This can be used to open a door or set off a trap when a lever is pulled or a brazier is extinguished.
When a placeable object is used.
GetLastUsedBy() returns the last object that used the placeable object.
You can use DoPlaceableObjectAction to make a lever move position (EG: On or Off), and SetPlaceableIllumination can turn on/off a light source, for example, a brazier.