code: public static RubyRange<Integer> range(int start, int end) {
      return new RubyRange<>(IntegerSuccessor.getInstance(), start, end,
          Interval.CLOSED);
    }
docs: Creates a {@link RubyRange} by given integers.
  
  @param start
  of the range
  @param end
  of the range
  @return {@link RubyRange}