code: public function setFormat($value)
      {
          if (is_array($value)) {
              if (!isset($value['class'])) {
                  $value['class'] = $this->determineFormatClass();
              }
              $value['field'] = $this;
              $value = Yii::createObject($value);
          }
          $this->_format = $value;
      }
docs: Set format.
  
  @param unknown $value
  
  @return unknown