static function PrintValue($array, $useCDATA = true)
 {
     $xml = '';
     if (is_array($array)) {
         foreach ($array as $key => $value) {
             if (is_null($value)) {
                 continue;
             } else {
                 if (is_array($value)) {
                     if (is_numeric($key)) {
                         $xml .= Respond::PrintValue($value, $useCDATA) . "\n";
                     } else {
                         $xml .= "<{$key}>" . Respond::PrintValue($value, $useCDATA) . "</{$key}>\n";
                     }
                 } else {
                     if ($useCDATA) {
                         $xml .= "<{$key}><![CDATA[" . Respond::escapeCData($value) . "]]></{$key}>\n";
                     } else {
                         $xml .= "<{$key}>" . htmlspecialchars($value) . "</{$key}>\n";
                     }
                 }
             }
         }
     }
     return $xml;
 }