}
          } else if (complementLowerBoundWindow.lowerBound.isLessThan(Cut.<C>belowAll())) {
            Range<C> negativeRange = Range.create(Cut.<C>belowAll(), nextComplementRangeUpperBound);
            nextComplementRangeUpperBound = Cut.belowAll();
            return Maps.immutableEntry(Cut.<C>belowAll(), negativeRange);
          }
          return endOfData();
        }
      };
    }