public TextScheduleWeekViewer(IScheduleDayViewer <string> dayViewer)
 {
     _dayViewer = dayViewer ?? throw new ArgumentNullException(nameof(dayViewer));
 }
 public OutputFormsController(IOutputForms outputForms, IScheduleDayViewer <string> dayViewer, IScheduleWeekViewer <string> weekViewer)
 {
     _outputForms = outputForms ?? throw new ArgumentNullException(nameof(outputForms));
     _dayViewer   = dayViewer ?? throw new ArgumentNullException(nameof(dayViewer));
     _weekViewer  = weekViewer ?? throw new ArgumentNullException(nameof(weekViewer));
 }