'Creates an empty content database for the Khan channel. This ensures
that an empty content database exists in the default distribution and
for tests.
Especially useful for creating an *EMPTY TEMPLATE*
retrievecontentpack empty en --template'

def empty(self, *args, **options):

    lang = args[1]
    if (not options.get('template', False)):
        content_db_path = topic_settings.CONTENT_DATABASE_PATH.format(channel=topic_settings.CHANNEL, language=lang)
    else:
        content_db_path = topic_settings.CONTENT_DATABASE_TEMPLATE_PATH.format(channel=topic_settings.CHANNEL, language=lang)
    if os.path.exists(content_db_path):
        if options.get('force', False):
            os.unlink(content_db_path)
        else:
            raise CommandError('Content    database    already    exists:    {}'.format(content_db_path))
    db = SqliteDatabase(content_db_path)
    db.connect()
    db.create_table(Item, safe=True)
    db.create_table(AssessmentItem, safe=True)
    db.close()
    self.complete(_('Saved    empty    content    database    in    {}.').format(content_db_path))
