Returns the offer class with the given class ID.
||The unique identifier for a class. This ID must be unique across all classes from an issuer. This value should follow the format issuer ID.identifier where the former is issued by Google and latter is chosen by you. Your unique identifier should only include alphanumeric characters, '.', '_', or '-'.|
This request requires authorization with the following scope (read more about authentication and authorization).
Do not supply a request body with this method.
If successful, this method returns an Offerclass resource in the response body.