private function addTextToTooltipInASet($seriesname, $index, Cotation $cotation)
 {
     $text = "Abertura: " . $cotation->getOpen();
     $text .= "\nFechamento: " . $cotation->getClose();
     $text .= "\nMaximo: " . $cotation->getMax();
     $text .= "\nMinimo: " . $cotation->getMin();
     $text .= "\nData: " . $cotation->getDate();
     $this->multiSeries->addAttributeToASet("tooltext", $text, $index, $seriesname);
 }