Delete repeater field via api gives error

[fliwire]

page has shipments ( repeater field ) with file field.

$shipment = pages()->get($input->post->shipment_id);
$shipment->of(false);
$pages->delete($page, true);
 

$page->of(false);
$page->shipments->remove($pages->get($input->post->shipment_id));
$page->save();

both of work but give 500 error..  delete page with ajax. 
In console " Error: Call to a member function numChildren() on null (line 431 of \wire\core\PagesEditor.php) "

[fliwire]

edited first code: 

$shipment = pages()->get($input->post->shipment_id);
$shipment->of(false);
$pages->delete($shipment, true);

pw 3.0.98

[fliwire]

fixed:)  it was my fault.