/// <summary>
        /// Creates a campaign ad extension for running further tests.
        /// </summary>
        /// <param name="user">The AdWords user.</param>
        /// <param name="campaignId">The campaign id for which extension is
        /// created.</param>
        /// <returns>The campaign ad extension id.</returns>
        public long CreateLocationExtension(AdWordsUser user, long campaignId)
        {
            CampaignAdExtensionService campaignExtensionService =
              (CampaignAdExtensionService) user.GetService(AdWordsService.v201309.
               CampaignAdExtensionService);

              CampaignAdExtensionOperation operation = new CampaignAdExtensionOperation();
              operation.@operator = Operator.ADD;

              CampaignAdExtension extension = new CampaignAdExtension();
              extension.campaignId = campaignId;
              extension.status = CampaignAdExtensionStatus.ACTIVE;

              Address address = new Address();
              address.streetAddress = "1600 Amphitheatre Pkwy, Mountain View";
              address.countryCode = "US";

              GeoLocation location = GetLocationForAddress(user, address);

              LocationExtension locationExtension = new LocationExtension();

              // Note: Do not populate an address directly. Instead, use
              // GeoLocationService to obtain the location of an address,
              // and use the address as per the location it returns.
              locationExtension.address = location.address;
              locationExtension.geoPoint = location.geoPoint;
              locationExtension.encodedLocation = location.encodedLocation;
              locationExtension.source = LocationExtensionSource.ADWORDS_FRONTEND;

              extension.adExtension = locationExtension;
              operation.operand = extension;
              CampaignAdExtensionReturnValue retVal =
              campaignExtensionService.mutate(new CampaignAdExtensionOperation[] {operation});
              return retVal.value[0].adExtension.id;
        }
        /// <summary>
        /// Runs the code example.
        /// </summary>
        /// <param name="user">The AdWords user.</param>
        /// <param name="campaignId">Id of the campaign to which location
        /// extensions are added.</param>
        public void Run(AdWordsUser user, long campaignId)
        {
            // Get the CampaignAdExtensionService.
              CampaignAdExtensionService campaignExtensionService =
              (CampaignAdExtensionService) user.GetService(AdWordsService.v201309.
              CampaignAdExtensionService);

              // Add location 1: 1600 Amphitheatre Pkwy, Mountain View, US.
              Address address1 = new Address();
              address1.streetAddress = "1600 Amphitheatre Parkway";
              address1.cityName = "Mountain View";
              address1.provinceCode = "CA";
              address1.postalCode = "94043";
              address1.countryCode = "US";

              // Add location 2: 38 avenue de l'Opéra, 75002 Paris, FR.
              Address address2 = new Address();
              address2.streetAddress = "38 avenue de l'Opéra";
              address2.cityName = "Paris";
              address2.postalCode = "75002";
              address2.countryCode = "FR";

              // Get the GeoLocationService.
              GeoLocationService geoService =
              (GeoLocationService) user.GetService(AdWordsService.v201309.GeoLocationService);

              // Create the selector.
              GeoLocationSelector selector = new GeoLocationSelector();
              selector.addresses = new Address[] {address1, address2};

              // Retrieve the locations.
              GeoLocation[] locations = geoService.get(selector);

              List<CampaignAdExtensionOperation> operations = new List<CampaignAdExtensionOperation>();

              // Phone numbers for US and FR offices.
              string[] phoneNumbers = new string[] {"(650) 253-0000", "(0)1 42 68 53 00"};
              int index = 0;

              // Create a location extension for each geo location returned by the
              // server.
              foreach (GeoLocation location in locations) {
            LocationExtension locationExtension = new LocationExtension();
            locationExtension.address = location.address;
            locationExtension.geoPoint = location.geoPoint;
            locationExtension.encodedLocation = location.encodedLocation;
            locationExtension.source = LocationExtensionSource.ADWORDS_FRONTEND;

            // Optional: Set the company name.
            locationExtension.companyName = "ACME Inc.";

            // Optional: Set the phone number.
            locationExtension.phoneNumber = phoneNumbers[index];
            index++;

            CampaignAdExtension extension = new CampaignAdExtension();
            extension.campaignId = campaignId;
            extension.status = CampaignAdExtensionStatus.ACTIVE;
            extension.adExtension = locationExtension;

            CampaignAdExtensionOperation operation = new CampaignAdExtensionOperation();
            operation.@operator = Operator.ADD;
            operation.operand = extension;

            operations.Add(operation);
              }

              try {
            CampaignAdExtensionReturnValue retVal =
            campaignExtensionService.mutate(operations.ToArray());

            // Display the results.
            if (retVal != null && retVal.value != null && retVal.value.Length > 0) {
              foreach (CampaignAdExtension campaignExtension in retVal.value) {
            Console.WriteLine("Created a location extension with id = \"{0}\" and " +
                "status = \"{1}\"", campaignExtension.adExtension.id, campaignExtension.status);
              }
            } else {
              Console.WriteLine("No location extensions were created.");
            }
              } catch (Exception ex) {
            throw new System.ApplicationException("Failed to add location extension.", ex);
              }
        }