TripServiceKata.User.User.GetFriends C# (CSharp) Method

        public List<User> GetFriends()
        {
            return friends;
        }

 public List<Trip> GetTripsByUser(User.User user)
 {
     List<Trip> tripList = new List<Trip>();
     User.User loggedUser = UserSession.GetInstance().GetLoggedUser();
     bool isFriend = false;
     if (loggedUser != null)
     {
         foreach(User.User friend in user.GetFriends())
         {
             if (friend.Equals(loggedUser))
             {
                 isFriend = true;
                 break;
             }
         }
         if (isFriend)
         {
             tripList = TripDAO.FindTripsByUser(user);
         }
         return tripList;
     }
     else
     {
         throw new UserNotLoggedInException();
     }
 }