code: public static void disposeOf(final Map<?, ? extends Disposable> disposables) {
          if (disposables != null) {
              for (final Disposable disposable : disposables.values()) {
                  disposeOf(disposable);
              }
          }
      }
docs: Performs null checks and disposes of assets.
  
  @param disposables its values will be disposed of (if they exist). Can be null.