@Nullable
  private Node parseSelectorList() {
    Node node = parseConjunction();
    if (node == null || getToken() != TextMateSelectorToken.COMMA) {
      return node;
    }
    List<Node> children = new ArrayList<>();
    children.add(node);
    while (getToken() == TextMateSelectorToken.COMMA) {
      advance();
      Node child = parseConjunction();
      if (child == null) break;
      children.add(child);
    }
    return new SelectorList(children);
  }
@Nullable
  private Node parseSelectorList()