DocumentGeneratorManager::getPaymentBoundDocumentId

public function getPaymentBoundDocumentId(int $paymentId): ?int
{
	$binding = DocumentBindingTable::getList([
		'select' => ['DOCUMENT_ID'],
		'filter' => [
			'=ENTITY_NAME' => \CCrmOwnerType::OrderPaymentName,
			'=ENTITY_ID' => $paymentId,
		],
		'limit' => 1,
	])->fetchObject();

	return $binding ? $binding->get('DOCUMENT_ID') : null;
}