@SuppressWarnings("unchecked")
      T t = (T) valueOrSentinel;
      valueOrSentinel = SENTINEL;
      return t;
    }
  }

  /**
   * Adapts an {@code Enumeration} to the {@code Iterator} interface.
   *
   * <p>This method has no equivalent in {@link Iterables} because viewing an {@code Enumeration} as
   * an {@code Iterable} is impossible. However, the contents can be <i>copied</i> into a collection

        returned = true;
        return null;
      }
      throw new NoSuchElementException();
    }
  }

  /**
   * Adapts an {@code Enumeration} to the {@code Iterator} interface.
   *
   * <p>This method has no equivalent in {@link Iterables} because viewing an {@code Enumeration} as
   * an {@code Iterable} is impossible. However, the contents can be <i>copied</i> into a collection