public ValueTask <Exam> RemoveExamByIdAsync(Guid examId) =>
TryCatch(async() =>
{
ValidateExamId(examId);
Exam maybeExam = await storageBroker.SelectExamByIdAsync(examId);
ValidateStorageExam(maybeExam, examId);
return(await storageBroker.DeleteExamAsync(maybeExam));
});