public async Task <IActionResult> List(string sectionName)
        {
            var section = Classroom.Sections
                          .SingleOrDefault(s => s.Name == sectionName);

            if (section == null)
            {
                return(NotFound());
            }

            var submissionResults = await SubmissionService.GetSectionSubmissionsAsync
                                    (
                ClassroomName,
                ProjectName,
                CheckpointName,
                sectionName
                                    );

            return(View(submissionResults));
        }