<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def init(directory=None, multidb=False):
 """Creates a new migration repository"""

    if directory is None:
        directory = current_app.extensions['migrate'].directory
    config = Config()
    config.set_main_option('script_location', directory)
    config.config_file_name = os.path.join(directory, 'alembic.ini')
    config = current_app.extensions['migrate'].\
        migrate.call_configure_callbacks(config)
    if multidb:
        command.init(config, directory, 'flask-multidb')
    else:
        command.init(config, directory, 'flask')