code: public static boolean removeAll(
        Iterable<?> removeFrom, Collection<?> elementsToRemove) {
      return (removeFrom instanceof Collection)
          ? ((Collection<?>) removeFrom).removeAll(checkNotNull(elementsToRemove))
          : Iterators.removeAll(removeFrom.iterator(), elementsToRemove);
    }
docs: Removes, from an iterable, every element that belongs to the provided
  collection.
  
  <p>This method calls {@link Collection#removeAll} if {@code iterable} is a
  collection, and {@link Iterators#removeAll} otherwise.
  
  @param removeFrom the iterable to (potentially) remove elements from
  @param elementsToRemove the elements to remove
  @return {@code true} if any element was removed from {@code iterable}