private function getCustomSortingNames(string $className): array
    {
        $this->fillCache($className);

        return array_keys($this->customSortings[$className]);
    }
private function getCustomSortingNames(string $className): array
    {
        $this->fillCache($className);

        return array_keys($this->customSortings[$className]);
    }
private function getCustomSortingNames ( string $ className ) : array { $ this -> fillCache ( $ className ) ; return array_keys ( $ this -> customSortings [ $ className ] ) ; }
Get names for all custom sorting

@param string $className

@return string[]
Get names for all custom sorting