code: public UnicodeSet set(UnicodeSet other) {
          checkFrozen();
          list = other.list.clone();
          len = other.len;
          pat = other.pat;
          strings = new TreeSet<String>(other.strings);
          return this;
      }
docs: Make this object represent the same set as <code>other</code>.
  @param other a <code>UnicodeSet</code> whose value will be
  copied to this object