docs: @SuppressWarnings({"unchecked"})
  	public L add(N newChild, Kind newChildKind) {
  		getAst().setChanged();
  		L n = getAst().buildTree(newChild, newChildKind);
  		if (n == null) return null;
  		n.parent = (L) this;
  		children = children.append(n);
  		return n;
  	}