@Override
 public boolean equals(Object obj) {
   if (this == obj) return true;
   if (obj == null) return false;
   if (getClass() != obj.getClass()) return false;
   PersonNetwork other = (PersonNetwork) obj;
   if (network == null) {
     if (other.network != null) return false;
   } else if (!network.equals(other.network)) return false;
   return true;
 }