public IResult Add(Attendance attendance, decimal fee) { if (checkIsEnrolledBefore(attendance)) { try { _attendanceDal.Add(attendance); if (_studentService.AddFee(attendance.StudentId, fee)) { return(new SuccessResult("Enrolled course")); } else { return(new ErrorResult("Fee cannot be added")); } } catch (Exception) { return(new ErrorResult("Error occurred while enrolling")); } } else { return(new ErrorResult("Student already enrolled this course")); } }