private async Task <List <MissedClassViewModel> > GetMissedClassViewModelsAsync(IEnumerable <MissedClass> missedClasses)
        {
            var viewModels = new List <MissedClassViewModel>();

            foreach (var missedClass in missedClasses)
            {
                var group = await _studentApi.GetStudentGroupAsync(missedClass.StudentId);

                var student = await _studentApi.GetByIdAsync(missedClass.StudentId);

                var cls = await _classesApi.GetByIdAsync(missedClass.ClassId);

                var subject = await _subjectApi.GetByIdAsync(cls.SubjectId);


                viewModels.Add(new MissedClassViewModel
                {
                    Id          = missedClass.Id,
                    ClassId     = missedClass.ClassId,
                    Date        = cls.StartDate,
                    GroupName   = group.Name,
                    StudentId   = missedClass.StudentId,
                    StudentName = student.FirstName + " " + student.LastName,
                    SubjectName = subject.Name,
                });
            }

            return(viewModels);
        }
        private async Task <string> GetGroupNameAsync(int studentId)
        {
            var group = await _studentApi.GetStudentGroupAsync(studentId);

            return(group.Name);
        }