public static function render_shortcode($atts, $content = null)
 {
     $dataManager = new DataManager();
     $data = $dataManager->participants();
     $html = '<table class="hre-participants-wrapper" border="0">';
     $grouping = null;
     foreach ($data as $participant) {
         if ($grouping != $participant['gender']) {
             $title = '';
             switch ($participant['gender']) {
                 case 'Man':
                     $title = 'Mannen';
                     break;
                 case 'Vrouw':
                     $title = 'Vrouwen';
                     break;
             }
             $html .= "<tr><th colspan=\"2\" class=\"hre-participant-name\"><a name=\"{$participant['gender']}\">&nbsp;</a><h2>{$title}</h2></th></tr>";
             $grouping = $participant['gender'];
         }
         $html .= '<tr class="hre-participant">';
         $html .= "<td class=\"hre-participant-name\">{$participant['Name']}</td>";
         $html .= "<td class=\"hre-participant-city\">{$participant['city']}</td>";
         $html .= '</tr>';
     }
     $html .= '</table>';
     return $html;
 }
 public static function showStats()
 {
     $dataManager = new DataManager();
     $data = $dataManager->data();
     $stats = null;
     if (count($data) > 0) {
         foreach ($data as $item) {
             $stats[$item['order_item_name']] = $item['Total'];
         }
     }
     return $stats;
 }