public IEnumerable <SyntaxNode> GetNodes(SyntaxGenerator gen)
{
var required = Values.Select(SyntaxExts.ToLiteral);
var optional = Properties.ToDictionary(k => k.Key, v => SyntaxExts.ToLiteral(v.Value));
var assigns = SyntaxExts.ToSyntaxNodes(optional);
var args = required.Concat(assigns);
yield return(gen.Attribute(Name, attributeArguments: args));
}