private function getDataSet($label, $data, $index = 0)
    {
        $set = $this->datasets[$index];
        $set['label'] = $label;
        $set['data'] = $data;

        return $set;
    }
private function getDataSet($label, $data, $index = 0)
    {
        $set = $this->datasets[$index];
        $set['label'] = $label;
        $set['data'] = $data;

        return $set;
    }
private function getDataSet ( $ label , $ data , $ index = 0 ) { $ set = $ this -> datasets [ $ index ] ; $ set [ 'label' ] = $ label ; $ set [ 'data' ] = $ data ; return $ set ; }
Get the line dataset opbject
@param     $label
@param     $data
@param int $index
@return mixed
Get the line dataset opbject