code: public function retrieve()
      {
          $path = null;
          switch ($this->type) {
              case self::CHARGE_CREDIT:
                  $path = 'application_credits';
                  break;
              case self::CHARGE_ONETIME:
                  $path = 'application_charges';
                  break;
              default:
                  $path = 'recurring_application_charges';
                  break;
          }
  
          return $this
              ->shop
              ->api()
              ->rest('GET', "/admin/{$path}/{$this->charge_id}.json")->body->{substr($path, 0, -1)};
      }
docs: Gets the charge's data from Shopify.
  
  @return object