code: func (members Members) Intersect(otherMembers Members) Members {
  	var res Members
  	m := otherMembers.ByID()
  	for _, member := range members {
  		if _, exists := m[string(member.PKIid)]; exists {
  			res = append(res, member)
  		}
  	}
  	return res
  }
docs: // Intersect returns the intersection of 2 Members