/guava/guava/src/com/google/common/collect/StandardRowSortedTable.java
return new StandardRowSortedTable<R, C, V> ( sortedBackingMap ( ) .headMap ( toKey ) , factory ) .rowMap ( ) ;
public R lastKey() { return sortedBackingMap().lastKey(); } @Override public SortedMap<R, Map<C, V>> headMap(R toKey) { checkNotNull(toKey); <extra_id_0> } @Override public SortedMap<R, Map<C, V>> subMap(R fromKey, R toKey) { checkNotNull(fromKey); checkNotNull(toKey); return new StandardRowSortedTable<R, C, V>(sortedBackingMap().subMap(fromKey, toKey), factory)