Sokil\Mongo\Cursor::findOne PHP Method

    public function findOne()
    {
        $mongoDocument = $this->collection->getMongoCollection()->findOne($this->expression->toArray(), $this->fields);
        if (null === $mongoDocument) {
            return null;
        }
        if (true === $this->resultAsArray) {
            return $mongoDocument;
        }
        return $this->collection->hydrate($mongoDocument, $this->isDocumentPoolUsed());
    }