Method subSet

guava/src/com/google/common/collect/Maps.java:4037–4044

(
        @ParametricNullness K fromElement,
        boolean fromInclusive,
        @ParametricNullness K toElement,
        boolean toInclusive)

    }

    @Override
    public NavigableSet<K> subSet(
        @ParametricNullness K fromElement,
        boolean fromInclusive,
        @ParametricNullness K toElement,
        boolean toInclusive) {
      return map().subMap(fromElement, fromInclusive, toElement, toInclusive).navigableKeySet();
    }

    @Override
    public SortedSet<K> subSet(@ParametricNullness K fromElement, @ParametricNullness K toElement) {