Method apply

corpus/java/training/guava/collect/TreeBasedTable.java:329–332

(Map<C, V> input)

                backingMap.values(),
                new Function<Map<C, V>, Iterator<C>>() {
                  @Override
                  public Iterator<C> apply(Map<C, V> input) {
                    return input.keySet().iterator();
                  }
                }),
            comparator);