/// <summary>
        /// Checks if an enrollee with the given email and pin is in the
        /// database and that the pin is correct.
        /// </summary>
        /// <param name="email"></param>
        /// <param name="pin"></param>
        /// <returns></returns>
        public Enrollee LoginEnrollee(string email, string pin)
        {
            Enrollee enrollee = Mgr.GetEnrolleeByEmail(email);

            // since enrollee can be null we need to check if it is equal to true
            return(((enrollee.Email.Equals("guest@guest") &&
                     email.Equals("guest@guest") &&
                     pin == enrollee.Pin) ||
                    enrollee?.Login(email, pin) == true) ? enrollee: null);
        }