private static function dumpSet(FormControlSet $control)
    {
        $inner = '';
        foreach ($control as $innerControl) {
            $inner .= self::dumpScalar($innerControl);
        }
        return <<<EOT
<dt>{$control->getLabel()}</dt>
<dd>
\t<dl>{$inner}</dl>
</dd>
EOT;
    }
 protected function setImportedValue($value)
 {
     Assert::isTrue(is_array($value));
     if (!$this->getImportDuplicates()) {
         $value = array_unique($value);
     }
     if (!$this->getImportEmpty()) {
         $emptied = array();
         foreach ($value as $item) {
             if (!empty($item)) {
                 $emptied[] = $item;
             }
         }
         $value = $emptied;
     }
     return parent::setImportedValue($value);
 }