public void AggregateLevelOnlyValues(List<int> principals, ref int allow, ref int deny)
{
foreach (var permSet in this.PermissionSets)
{
if (permSet.Propagates)
continue;
if (!principals.Contains(permSet.PrincipalId))
continue;
allow |= permSet.AllowBits;
deny |= permSet.DenyBits;
}
}