code: private function plainBonus($bonus)
      {
          /* prepare data for updates */
          $result = [];
          /** @var DEntry $item */
          foreach ($bonus as $item) {
              $bonusData = $item->getEntries();
              /** @var DBonus $entry */
              foreach ($bonusData as $entry) {
                  $bonus = $entry->getValue();
                  if ($bonus > Cfg::DEF_ZERO) {
                      $result[] = $entry;
                  }
              }
          }
          return $result;
      }
docs: Convert 2D array with bonuses into 1D array.
  
  @param $bonus
  @return array