public string NewStudent(StudentSummary studentSummary)
{
if (Summaries.Count > 0)
{
studentSummary.ID = Summaries.Max(x => x.ID) + StudentConsts.IDStep;
}
else
{
studentSummary.ID = StudentConsts.IDStep;
}
Add(studentSummary);
WriteSummariesToFile();
return(StudentConsts.ResultOK);
}