code: public static <E extends Enum<E>> EnumSet<E> copyOf(EnumSet<E> s) {
          return s.clone();
      }
docs: Creates an enum set with the same element type as the specified enum
  set, initially containing the same elements (if any).
  
  @param <E> The class of the elements in the set
  @param s the enum set from which to initialize this enum set
  @return A copy of the specified enum set.
  @throws NullPointerException if <tt>s</tt> is null