find the different between 2 list

//DELETE

var oldDifferentList = oldSchool.Students.Except(newSchool.Students, new StudentComparer()).ToList();

//ADD 

var newDifferentList = newSchool.Students.Except(oldSchool.Students, new StudentComparer ()).ToList();

//EDIT

var statusChangedList = oldSchool.Students.Union(newSchool.Students).GroupBy(x => x.StudentID).Where(y => y.First().Status!= y.Last().Status).ToList();

//COMPARER

public class StudentComparer : IEqualityComparer<Student>

{

        public bool Equals(Student p1, Student p2)

        {

            if (Object.ReferenceEquals(p1, p2))

                return true;

            return p1.StudentID == p2.StudentID && p1.City == p2.City;

        }

        public int GetHashCode(Student obj)

        {

            if (Object.ReferenceEquals(obj, null)) return 0;

            int hashStudentID = obj.StudentID.GetHashCode();

            int hashCity = obj.City.GetHashCode();

            return hashStudentID ^ hashCity;

        }

}