public function getDPUBreakdown()
    {
        $retval = false;

        if (strlen(trim($this->_csdl)) == 0) {
            throw new DataSift_Exception_InvalidData('Cannot get the DPU for an empty definition.');
        }

        $retval = $this->_user->post('dpu', array('hash' => $this->getHash()));
        $this->_total_dpu = $retval['dpu'];
        return $retval;
    }