Doctrine\ODM\PHPCR\UnitOfWork::checkout PHP Method

    public function checkout($document)
    {
        $path = $this->getVersionedNodePath($document);
        $vm = $this->session->getWorkspace()->getVersionManager();
        $vm->checkout($path);
    }

 /**
  * {@inheritDoc}
  */
 public function checkout($document)
 {
     if (!is_object($document)) {
         throw new InvalidArgumentException('Parameter $document needs to be an object, ' . gettype($document) . ' given');
     }
     $this->errorIfClosed();
     $this->unitOfWork->checkout($document);
 }