Base::update

protected function update($id, array $fields)
{
	$entityTable = $this->getEntityTable();

	/** @var BitrixMainResult $r */
	$r = $this->exists($id);
	if($r->isSuccess())
	{
		return $entityTable::update($id, $fields);
	}
	else
	{
		$this->addErrors($r->getErrors());
		return null;
	}
}