# File lib/fog/softlayer/requests/network/get_subnet_package_id.rb, line 23
        def get_subnet_package_id(address_space)
          address_space.downcase!; err_msg = "Argument for #{self.class.name}##{__method__} must be 'PRIVATE' or 'PUBLIC'."
          raise ArgumentError, err_msg unless %{private public}.include?(address_space)
          request(:product_package, '0/get_configuration', :query => 'objectMask=mask[isRequired,itemCategory]').body.map do |item|
            item['itemCategory']['id'] if item['itemCategory']['categoryCode'] == 'static_sec_ip_addresses'
          end.compact.first
        end