private static void TryShowWantedData(string input, string[] data)
 {
     if (data.Length == 2)
     {
         string courseName = data[1];
         StudentsRepository.GetAllStudetsFromCourse(courseName);
     }
     else if (data.Length == 3)
     {
         string courseName = data[1];
         string userName   = data[2];
         StudentsRepository.GetStudentScoresFromCourse(courseName, userName);
     }
     else
     {
         DisplayInvalidCommandMessage(input);
     }
 }