Sokil\Mongo\Collection::isDocumentInDocumentPool PHP Method

    public function isDocumentInDocumentPool($document)
    {
        if ($document instanceof Document) {
            $document = $document->getId();
        }
        return isset($this->documentPool[(string) $document]);
    }

 public function testIsDocumentInDocumentPool()
 {
     $document = $this->collection->createDocument(array('field' => 'value'))->save();
     $this->assertTrue($this->collection->isDocumentInDocumentPool($document));
     $this->assertTrue($this->collection->isDocumentInDocumentPool($document->getId()));
     $this->assertTrue($this->collection->isDocumentInDocumentPool((string) $document->getId()));
     $this->assertFalse($this->collection->isDocumentInDocumentPool(42));
 }