code: @Pure
  	public static <T> TreeSet<T> newTreeSet(Comparator<? super T> comparator) {
  		return new TreeSet<T>(comparator);
  	}
docs: Creates an empty mutable {@link TreeSet} instance.
  
  @param comparator
  the comparator that should be used. May be <code>null</code> which indicates that the natural ordering
  of the items should be used.
  @return a new {@link TreeSet}
  
  @since 2.13