code: public function orderVpsInAvailabilityZone($productName, array $addons, $operatingSystemName, $hostname, $availabilityZone)
      {
          return $this->call(self::SERVICE, 'orderVps', [$productName, $addons, $operatingSystemName, $hostname, $availabilityZone]);
      }
docs: Order a VPS with optional add-ons.
  
  @param string   $productName         Name of the product
  @param string[] $addons              Array with additional add-ons
  @param string   $operatingSystemName Name of the operating system to install
  @param string   $hostname            Hostname for the VPS
  @param string   $availabilityZone    Availability zone for the VPS
  
  @throws \SoapFault
  
  @return mixed