/guava/android/guava/src/com/google/common/collect/AbstractMapBasedMultimap.java
collection.clear ( ) ;
if (collection == null) { return createUnmodifiableEmptyCollection(); } Collection<V> output = createCollection(); output.addAll(collection); totalSize -= collection.size(); <extra_id_0> return unmodifiableCollectionSubclass(output); } <E extends @Nullable Object> Collection<E> unmodifiableCollectionSubclass( Collection<E> collection) { return Collections.unmodifiableCollection(collection); }