Something

  class Test: Object {
    Datalist <SList <string>> data;

    public void test () {
      SList <string> list;
      
      list.prepend ("a");
      list.prepend ("b");
      list.prepend ("c");
      
      this.data.id_set_data_full (Quark.from_string ("wef"), list, null);
      
      assert (list.length () == 3);
      
      var v = this.data.id_get_data (Quark.from_string ("wef")).copy ();
      
      assert (v.length () == 3);
      
    }