Method headMap

corpus/java/training/guava/collect/Maps.java:917–920

(K toKey)

    }

    @Override
    public SortedMap<K, V> headMap(K toKey) {
      return asMap(backingSet().headSet(toKey), function);
    }

    @Override
    public SortedMap<K, V> tailMap(K fromKey) {