Inheritance: ITeacher
 public ITeacher CreateTeacher(string name)
 {
     var teacher = new Teacher(name);
     return teacher;
 }
 public ITeacher CreateTeacher(string name)
 {
     if (name == null)
     {
         throw new ArgumentNullException("Name cannot be null.");
     }
     else
     {
         ITeacher teacher = new Teacher();
         teacher.Name = name;
         return teacher;
     }
 }
        public ITeacher CreateTeacher(string name)
        {
            ITeacher teacher = new Teacher(name);

            return(teacher);
        }
 public ITeacher CreateTeacher(string name)
 {
     ITeacher newTeatcher = new Teacher(name);
     return newTeatcher;
 }