How do I add a checkmark to a table view?

I've put in this code:

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {

     UITableViewCell * tableCell = [self.tableView cellForRowAtIndexPath:indexPath];

     tableCell.accessoryType = UITableViewCellAccessoryCheckmark;
     [tableView deselectRowAtIndexPath:(NSIndexPath *)indexPath animated:YES];

}
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But for some reason, the checkmark doesn't appear. Could someone help?

Actaully, I figured it out, that's the right way to do it, its just it had a black bg so it was hard to see.