code: public static long maximumLength(final Iterable<Range<Long>> ranges) {
          checkNotNull(ranges);
          if (Iterables.isEmpty(ranges)) {
              return -1L;
          }
          return Ordering.natural().max(lengths(ranges)).longValue();
      }
docs: Return the maximum length in the specified ranges, or <code>-1</code> if ranges is empty.
  
  @param ranges ranges, must not be null, must not contain any null ranges, and all ranges must be [closed, open)
  @return the maximum length in the specified ranges, or <code>-1</code> if ranges is empty