Sokil\Mongo\Collection::getDocumentClassName PHP Method

    public function getDocumentClassName(array $documentData = null)
    {
        $documentClass = $this->definition->getOption('documentClass');
        if (is_callable($documentClass)) {
            return call_user_func($documentClass, $documentData);
        }
        if (class_exists($documentClass)) {
            return $documentClass;
        }
        throw new Exception('Property "documentClass" must be callable or valid name of class');
    }