public person LookUpFriends(int ID, int machineID) // give a userID, machineID look for friend
    {
        for(Machine m : server.machineList)
        {       
            if (m.machineID == machineID) 
            {
                for(person p : m.personList)
                {
                    if (p.PID== ID)
                        return p;
                }
            }   
        }
        return null ;
    }