* @return Cons
   */
  public Cons prepend(Cons list1) {
    { Cons self = this;

      if (list1 == Stella.NIL) {
        return (self);
      }
      { Cons copy1 = Cons.copyConsList(list1);

        copy1.concatenate(self, Stella.NIL);
        return (copy1);
      }
    }
  }