name::saveByEntity

protected function saveByEntity(MainEntityBase $entity, $id, array $data, $primary = null)
{
	/** @var BitrixMainEntityDataManager $className Class name. */
	$className = $entity->getDataClass();

	$primary = $primary ?: $id;

	if($id)
	{
		if (array_key_exists('ID', $data))
		{
			unset($data['ID']);
		}
		$resultDb = $className::update($primary, $data);
	}
	else
	{
		$resultDb = $className::add($data);
		$id = $resultDb->getId();
	}

	if(!$resultDb->isSuccess())
	{
		$this->errors->add($resultDb->getErrors());
	}

	return $id;
}