Adding Image extensions through Google ads API

I am using this script based on the documentation: https://developers.google.com/google-ads/api/samples/add-image-extension

def create_image_extensions(df):     for index,row in df.iterrows():         extension_feed_item_service =              client.get_service("ExtensionFeedItemService")         extension_feed_item_operation =              client.get_type("ExtensionFeedItemOperation")         extension_feed_item = extension_feed_item_operation.create         extension_feed_item.image_feed_item.image_asset =               client.get_service("AssetService").asset_path(account_id,                  row.asset_id)         response = extension_feed_item_service.mutate_extension_feed_items(customer_id=account_id, operations=\[extension_feed_item_operation\])         image_resource_name = response.results\[0\].resource_name         print("Created an image extension with resource name: "f"'{image_resource_name}'")             campaign_extension_setting_service = client.get_service("CampaignExtensionSettingService")         campaign_extension_setting_operation = client.get_type("CampaignExtensionSettingOperation")         ces = campaign_extension_setting_operation.create         ces.campaign = client.get_service("CampaignService").campaign_path(account_id, row.campaign_id)         ces.extension_type = client.enums.ExtensionTypeEnum.IMAGE         ces.extension_feed_items.append(image_resource_name)              response = (             campaign_extension_setting_service.mutate_campaign_extension_settings(                 customer_id=account_id,                 operations=[campaign_extension_setting_operation],             )         )         print("Created a campaign extension setting with resource name: "f"'{response.results[0].resource_name}'")` 

But running into an error now:

Method: /google.ads.googleads.v15.services.ExtensionFeedItemService/MutateExtensionFeedItems, RequestId: B5OFT8TdalKrrmx0lEdMkA, IsFault: True, FaultMessage: Feed-based extension is read-only for this extension type. error_code {     feed_error: LEGACY_EXTENSION_TYPE_READ_ONLY   }   message: "Feed-based extension is read-only for this extension type."