code: public static Tree CCtransform(Tree t) {
      boolean notDone = true;
      while (notDone) {
        Tree cc = findCCparent(t, t);
        if (cc != null) {
          t = cc;
        } else {
          notDone = false;
        }
      }
      return t;
    }
docs: Transforms t if it contains a coordination in a flat structure
  
  @param t a tree to be transformed
  @return t transformed (give t not null, return will not be null)