PHP SDK REST API update note error

code:

$item = $api->notes()->find($id);
$item->body = 'world';
$item->title = 'hello';
$item->save();

results in

Client error: PATCH https://api.infusionsoft.com/crm/rest/v1/notes/473?access_token=1234567890 resulted in a 400 Bad Request response:
{“message”:“Unrecognized property: id”}

solution?