protected function canonicalize(\DOMNode $object)
	{		
		$options = $this->c14nOptionMapping[$this->canonicalMethod];
		
		// canonicalize the provided data with the preset options
		$c14nData = $object->C14N($options['exclusive'], $options['withComments']);
		
		if (is_string($c14nData) && strlen($c14nData))
		{
			return $c14nData;
		}
		
		throw new \UnexpectedValueException('Unable to canonicalize the provided DOM document');
	}