Doctrine\ODM\MongoDB\DocumentManager::contains PHP Method

    public function contains($document)
    {
        if (!is_object($document)) {
            throw new \InvalidArgumentException(gettype($document));
        }
        return $this->unitOfWork->isScheduledForInsert($document) || $this->unitOfWork->isInIdentityMap($document) && !$this->unitOfWork->isScheduledForDelete($document);
    }