Method subSet

guava/src/com/google/common/collect/Maps.java:1152–1156

(
          @ParametricNullness E fromElement, @ParametricNullness E toElement)

      }

      @Override
      public SortedSet<E> subSet(
          @ParametricNullness E fromElement, @ParametricNullness E toElement) {
        return removeOnlySortedSet(super.subSet(fromElement, toElement));
      }

      @Override
      public SortedSet<E> tailSet(@ParametricNullness E fromElement) {