public function deleteChartTitle($chartIndex)
    {
        //check whether workshett name is set or not
        if ($this->worksheetName == '')
            throw new Exception('Worksheet name not specified');
        
        if (!isset($chartIndex))
            throw new Exception('Chart Index not specified');
        
        $strURI = Product::$baseProductUri . '/cells/' . $this->getFileName() . '/worksheets/' . $this->worksheetName . '/charts/' . $chartIndex . '/title';
        
        $signedURI = Utils::sign($strURI);
        
        $response = Utils::processCommand($signedURI, 'DELETE', '', '');
        
        $json = json_decode($response);
        
        if ($json->Code == 200)
            return true;
        else
            return false;
    }