A single mutate operation on the user list customer type.

[Proto definition ![GitHub](https://developers.google.com/site-assets/logo-github.svg)](https://github.com/googleapis/googleapis/blob/master/google/ads/googleads/v25/services/user_list_customer_type_service.proto)

| Fields ||
|---|---|
| ## `operation` Union field. The mutate operation. `operation` can be only one of the following: ||
| ### `create` | `https://developers.google.com/google-ads/api/reference/rpc/v25/UserListCustomerType` Attach a user list customer type to a user list. No resource name is expected for the new user list customer type. |
| ### `remove` | `string` Remove an existing user list customer type. A resource name for the removed user list customer type is expected, in this format: `customers/{customer_id}/userListCustomerTypes/{user_list_id}~{customer_type_category}` |