def _get_choices(self, gandi):
        """ Internal method to get choices list """
        image_list = []
        for item in gandi.image.list():
            label = item['label']
            if item['visibility'] == 'deprecated':
                label = '*%s' % label
            image_list.append(label)
        disk_list = [item['name'] for item in gandi.disk.list_create()]
        return sorted(tuple(set(image_list))) + disk_list
Internal method to get choices list