code: @Inline(value="$3.removeAll($1, $2)", imported=Iterables.class)
  	public static <E> boolean operator_remove(Collection<E> collection, Collection<? extends E> newElements) {
  		return removeAll(collection, newElements);
  	}
docs: The operator mapping from {@code -=} to {@link #removeAll(Collection, Collection)}. Returns <code>true</code> if the
  collection changed due to this operation.
  
  @param collection
  the to-be-changed collection. May not be <code>null</code>.
  @param newElements
  elements to be removed from the collection. May not be <code>null</code> but may contain
  <code>null</code> elements if the the target collection supports <code>null</code> elements.
  @return <code>true</code> if the collection changed due to this operation.
  @see #removeAll(Collection, Collection)
  @since 2.4