public Iterator<T> insertBefore(Iterator<T> itr, T o) {	// Insert BEFORE iterator
		LinkedNode cur = ((LinkedIterator) itr).curNode;
		LinkedNode newNode = new LinkedNode(cur.previousNode, cur, o);
		cur.previousNode.nextNode = newNode;
		cur.previousNode = newNode;
		return new LinkedIterator(newNode);
	}
Insert new object BEFORE object pointed to by iterator, other Iterators remain valid

@param itr  Iterator to existing object
@param o   New object to add
@return      Iterator to new object
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/model/pcode/ListLinked.java