code: func (s *OrderedSet) Equal(other *OrderedSet) bool {
  	if s.Cardinality() != other.Cardinality() {
  		return false
  	}
  
  	for e, i := range s.m {
  		if ci, ok := other.m[e]; !ok || ci != i {
  			return false
  		}
  	}
  
  	return true
  }
docs: // Equal returns whether this element has the same number, identity and ordering
  // elements as given in "other".