# difference method

Set<E> difference (Set<Object> other)

Returns a new set with the elements of this that are not in `other`.

That is, the returned set contains all the elements of this Set that are not elements of `other` according to `other.contains`.

## Implementation

    Set<E> difference(Set<Object> other) {
      Set<E> result = toSet();
      for (E element in this) {
        if (other.contains(element)) result.remove(element);
      }
      return result;
    }