if (o == null || !(o instanceof SexpList))
if (this == o) return true; if (!(o instanceof SexpList))
  public boolean equals(Object o) {    if (o == null || !(o instanceof SexpList))      return false;    SexpList sexpList = (SexpList)o;    return (list.size() == sexpList.list.size() &&	    list.equals(sexpList.list));  }