Inserts nodes before this animation node.
If there is no parent animation group, terminate these steps. If any of the animation nodes in nodes is an inclusive ancestor of this animation node throw a HierarchyRequestError exception and terminate these steps. Insert nodes before this animation node. Note that this definition precludes the following usage since node is an inclusive ancestor of itself:
node.before(node); // throws HierarchyRequestError
var = .before(AnimationNode...nodes);
Takes a series of AnimationNodes as an object.
Returns an object of type