code: public static function loadMultiple($models, $data, $formName = null)
      {
          if ($formName === null) {
              /* @var $first Model|false */
              $first = reset($models);
              if ($first === false) {
                  return false;
              }
              $formName = $first->formName();
          }
  
          $success = false;
          foreach ($models as $i => $model) {
              /* @var $model Model */
              if ($formName == '') {
                  if (!empty($data[$i]) && $model->load($data[$i], '')) {
                      $success = true;
                  }
              } elseif (!empty($data[$formName][$i]) && $model->load($data[$formName][$i], '')) {
                  $success = true;
              }
          }
  
          return $success;
      }
docs: Populates a set of models with the data from end user.
  This method is mainly used to collect tabular data input.
  The data to be loaded for each model is `$data[formName][index]`, where `formName`
  refers to the value of [[formName()]], and `index` the index of the model in the `$models` array.
  If [[formName()]] is empty, `$data[index]` will be used to populate each model.
  The data being populated to each model is subject to the safety check by [[setAttributes()]].
  @param array $models the models to be populated. Note that all models should have the same class.
  @param array $data the data array. This is usually `$_POST` or `$_GET`, but can also be any valid array
  supplied by end user.
  @param string $formName the form name to be used for loading the data into the models.
  If not set, it will use the [[formName()]] value of the first model in `$models`.
  This parameter is available since version 2.0.1.
  @return bool whether at least one of the models is successfully populated.