bool setChosenSubject(int subjectId)
        {
            var subject = CurrentSubjects.SingleOrDefault(
                s => s.Id == subjectId);

            return(setChosenSubject(subject));
        }
        protected void subjectChosen(object chosenObject)
        {
            try {
                var id = Convert.ToInt32(chosenObject);

                if (id == -1)
                {
                    return;
                }

                var subject  = CurrentSubjects.SingleOrDefault(s => s.Id == id);
                var isChosen = setChosenSubject(subject);

                if (isChosen)
                {
                    SubjectChanged?.Invoke(PlatformServices.Preferences.ChosenSubjectId, subject.Name);
                }
            } catch (Exception ex) {
                AppLogs.Log(ex);
            }
        }