public async Task <IActionResult> DeleteConfirmed(int id)
{
var groups = await _servGroups.DeleteConfirmedAsync(id);
if (groups != null)
{
ViewData["ErrorMessage"] =
"Delete failed. This group is not empty. Transfer students to a different group " +
"and try again.";
return(View(groups));
}
return(RedirectToAction(nameof(Index)));
}