public function prepend($sTarget, $sAttribute, $sData)
    {
        return $this->addCommand(
            array(
                'cmd' => 'pp',
                'id' => trim((string)$sTarget, " \t"),
                'prop' => trim((string)$sAttribute, " \t")
            ),
            trim((string)$sData, " \t\n")
        );
    }