protected override bool NotEqual(ElaValue left, ElaValue right, ExecutionContext ctx)
{
var lg = left.As<ElaGuid>();
var rg = right.As<ElaGuid>();
if (lg != null && rg != null)
return lg.Value != rg.Value;
else if (lg != null)
return right.NotEqual(left, right, ctx);
return true;
}