/**
  * Provides default behavior for rendering fields
  * @param string $method
  * @param array $args
  */
 function __call($method, $args)
 {
     if (preg_match("/render_([\\w_]+)/", $method, $matches) && !$this->has_method($method)) {
         $field_name = $matches[1];
         $value = isset($this->_display_type->{$field_name}) ? $this->_display_type->{$field_name} : '';
         return $this->render_partial($field_name, array('value' => $value, 'context' => $this->_display_type->context), TRUE);
     } else {
         return parent::__call($method, $args);
     }
 }