def METHOD_NAME(self, release):
    '''
    Called to retrieve release information when expanding a release in the Tag Sources Tree view
    :param release: A dict containing information about an album release
    :return: a 2-tuple containing
                a dict of album release tags/fields and their values, and
                a list of dicts containing album track tags/fields and their values
    '''
    raise UnimplementedMethod("TagsSource.retrieve")