code: func (s *OrderedSet) IsSubset(other *OrderedSet) bool {
  	for _, i := range other.s {
  		if !s.Contains(i) {
  			return false
  		}
  	}
  	return true
  }
docs: // IsSubset returns whether other is a subset of this ordered set. In other
  // words, it returns whether or not all of the elements in "other" are also
  // present in this set.