Contao\Model::getPk PHP Метод

    public static function getPk()
    {
        return static::$strPk;
    }

 /**
  * Unregister an alias
  *
  * @param Model  $objModel The model object
  * @param string $strAlias The alias name
  * @param mixed  $varValue The value of the alias
  *
  * @throws \InvalidArgumentException If the alias is not registered
  */
 public function unregisterAlias(Model $objModel, $strAlias, $varValue)
 {
     $strTable = $objModel->getTable();
     if (!isset($this->arrAliases[$strTable][$strAlias][$varValue])) {
         $strPk = $objModel->getPk();
         $varPk = $objModel->{$strPk};
         throw new \RuntimeException("The registry does not contain an alias for {$strTable}::{$strPk}({$varPk}) ({$strAlias}/{$varValue})");
     }
     unset($this->arrAliases[$strTable][$strAlias][$varValue]);
 }