code: public function setCurrency($currency)
      {
          $allowed_values = array('AUD', 'NZD');
          if ((!in_array($currency, $allowed_values))) {
              throw new \InvalidArgumentException("Invalid value for 'currency', must be one of 'AUD', 'NZD'");
          }
          $this->container['currency'] = $currency;
  
          return $this;
      }
docs: Sets currency
  @param string $currency The currency
  @return $this