protected Course(string name, ITeacher teacher)
        {
            this.Name = name;
            this.Teacher = teacher;

            program = new List<string>();
        }

    public IOffsiteCourse CreateOffsiteCourse(string name, ITeacher teacher, string town)
    {
        //returns a offsiteCourse object
        IOffsiteCourse newLocalCourse = new OffsiteCourse(name, teacher, town);

        return newLocalCourse;
    }

    public ILocalCourse CreateLocalCourse(string name, ITeacher teacher, string lab)
    {
        //returns a localCourse object
        ILocalCourse newLocalCourse = new LocalCourse(name, teacher, lab);

        return newLocalCourse;
    }

        public Course(string name, ITeacher teacher)
        {
            this.Name = name;
            this.Teacher = teacher;

            this.Topics = new List<string>();
        }

        public int AddTeacher(ITeacher teacher)
        {
            var id = this.idProvider.GenerateTeacherId();

            this.teachers.Entities.Add(id, teacher);

            return id;
        }

 public ClassInfo(DateTime dateOfConduction, DateTime  classStartHour, DateTime classEndHour, ITeacher teacher, ICourse course)
 {
     this.DateOfConduction = dateOfConduction;
     this.ClassStartHour = classStartHour;
     this.ClassEndHour = classEndHour;
     this.ClassLengthInMinutes = this.CalculateClassLengthInMinutes(this.ClassStartHour, this.ClassEndHour);
     this.ConductedClassHours = this.CalculateNumberOfHoursTaken(this.ClassLengthInMinutes);
     this.Teacher = teacher;
     this.Course = course;
 }

 public LocalCourse(string name, ITeacher teacher, string lab)
     : base(name, teacher)
 {
     if (lab != null)
     {
         this.Lab = lab;
     }
     else
     {
         throw new ArgumentNullException();
     }
 }

 public OffsiteCourse(string name, ITeacher teacher, string town)
     : base(name, teacher)
 {
     if (town != null)
     {
         this.Town = town;
     }
     else
     {
         throw new ArgumentNullException();
     }
 }

 public LocalCourses(string name, ITeacher teacher, string lab)
 {
     if (name == null || lab == null)
     {
         throw new ArgumentNullException();
     }
     this.Topic = new List<string>();
     this.Type = CourseType.LocalCourse;
     this.Name = name;
     this.Teacher = teacher;
     this.Lab = lab;
 }

 public Course(string name, ITeacher teacher)
 {
     if (name != null)
     {
         this.Teacher = teacher;
         this.Name = name;
         this.Topics = new List<string>();
     }
     else
     {
         throw new ArgumentNullException();
     }
 }

 public OffsiteCourses(string name, ITeacher teacher, string town)
 {
     if (name == null || town == null)
     {
         throw new ArgumentNullException();
     }
     else
     {
         this.Topic = new List<string>();
         this.Type = CourseType.OffsiteCourse;
         this.Name = name;
         this.Teacher = teacher;
         this.Town = town;
     }
 }

 public Automata( ITeacher te, DayPeriod time)
 {
     Console.Out.Write("Create Automata Course object : ");
     Console.Out.WriteLine(time);
     gradCourse = false;
 }

 protected Course(string name, ITeacher teacher)
     : base(name)
 {
     this.Teacher = teacher;
     this.courseTopics = new List<string>();
 }

 protected Course(string name, ITeacher teacher)
 {
     this.Name = name;
     this.Teacher = teacher;
     this.topics = new LinkedList<string>();
 }

 public LocalCourses(string name, ITeacher teacher, string lab)
     : base(name, teacher)
 {
     this.Lab = lab;
 }

 public IOffsiteCourse CreateOffsiteCourse(string name, ITeacher teacher, string town)
 {
     return new OffsiteCourse(name, teacher, town);
 }

 public LocalCourse(string name, string lab, ITeacher teacher = null)
     : base(name, teacher)
 {
     this.Lab = lab;
 }

 public ILocalCourse CreateLocalCourse(string name, ITeacher teacher, string lab)
 {
     var localCourse = new LocalCourse(name, teacher, lab);
     return localCourse;
 }

 public OS(ITeacher te, DayPeriod time)
 {
     Console.Out.Write("Create OS Course object : ");
     Console.Out.WriteLine(time);
     gradCourse = true;
 }

 public LocalCourse(string name, ITeacher teacher, string lab)
     : base(name)
 {
     this.Teacher = teacher;
     this.lab = lab;
 }