/guava/android/guava/src/com/google/common/collect/AbstractMapBasedMultimap.java
return sortedMap ( ) .firstKey ( ) ;
public Comparator<? super K> comparator() { return sortedMap().comparator(); } @Override @ParametricNullness public K first() { <extra_id_0> } @Override public SortedSet<K> headSet(@ParametricNullness K toElement) { return new SortedKeySet(sortedMap().headMap(toElement)); } @Override