guava/src/com/google/common/collect/Multimaps.java
@Deprecated
  public static <K, V> SetMultimap<K, V> unmodifiableSetMultimap(
      ImmutableSetMultimap<K, V> delegate) {
    return checkNotNull(delegate);
  }
@Deprecated
  public static <K, V> SetMultimap<K, V> unmodifiableSetMultimap(
      ImmutableSetMultimap<K, V> delegate) {
    return checkNotNull(delegate);
  }
@ Deprecated public static < K , V > SetMultimap < K , V > unmodifiableSetMultimap ( ImmutableSetMultimap < K , V > delegate ) { return checkNotNull ( delegate ) ; }
Simply returns its argument.

@deprecated no need to use this
@since 10.0
Simply returns its argument .