public function hasPropertyValue(Node $node = null, $property, $value) {
        if (!isset($node))
            return false;
        $valuesFromNode = $node->getProperty($this->expand($property));
        if (!isset($valuesFromNode))
            return false;
        if (!is_array($valuesFromNode))
            $valuesFromNode = array($valuesFromNode);
        
        foreach ($valuesFromNode as $v) {
            if (is_a($v, 'ML\JsonLD\Node')) {
                if ($v->getId() == $this->expand($value))
                    return true;
            } else {
                if ($v->getValue() == $value)
                    return true;
            }                
        }
        
        return false;
    }