private function prepareValues($values)
 {
     if (!$values) {
         return array();
     }
     $submit = array();
     foreach ($values as $name => $value) {
         $field = new Field($name, $this->typeForFieldName($name));
         $submit = array_merge($submit, $field->prepareValues($value));
     }
     return $submit;
 }