docs: @Pure
  	public static <K, V> Map<K, V> operator_minus(Map<K, V> map, final Iterable<?> keys) {
  		return Maps.filterKeys(map, new Predicate<K>() {
  			@Override
  			public boolean apply(K input) {
  				return !Iterables.contains(keys, input);
  			}
  		});
  	}