human
Complete this python program:
def create_or_verify_database(url, galaxy_config_file, engine_options={}, app=None):
assistant
#Here is the Python program you requested.

    """Check that the database is use-able, possibly creating it if empty (this is
    the only time we automatically create tables, otherwise we force the
    user to do it using the management script so they can create backups).
    1) Empty database --> initialize with latest version and return
    2) Database older than migration support --> fail and require manual update
    3) Database at state where migrate support introduced --> add version control information but make no changes (might still require manual update)
    4) Database versioned but out of date --> fail with informative message, user must run "sh manage_db.sh upgrade"
    """
    engine = create_engine(url, **engine_options)
    def migrate():
        try:
            db_schema = schema.ControlledSchema.create(engine, migrate_repository)
        except:
            db_schema = schema.ControlledSchema(engine, migrate_repository)
        migrate_to_current_version(engine, db_schema)
    meta = MetaData(bind=engine)
    if (app and getattr(app.config, 'database_auto_migrate', False)):
        migrate()
        return
    try:
        Table('dataset', meta, autoload=True)
    except NoSuchTableError:
        if app:
            app.new_installation = True
        log.info('No    database,    initializing')
        migrate()
        return
    try:
        hda_table = Table('history_dataset_association', meta, autoload=True)
    except NoSuchTableError:
        raise Exception('Your    database    is    older    than    hg    revision    1464:c7acaa1bb88f    and    will    need    to    be    updated    manually')
    if ('copied_from_history_dataset_association_id' not in hda_table.c):
        raise Exception('Your    database    is    older    than    hg    revision    1464:c7acaa1bb88f    and    will    need    to    be    updated    manually')
    try:
        Table('migrate_version', meta, autoload=True)
    except NoSuchTableError:
        log.info('Adding    version    control    to    existing    database')
        try:
            Table('metadata_file', meta, autoload=True)
            schema.ControlledSchema.create(engine, migrate_repository, version=2)
        except NoSuchTableError:
            schema.ControlledSchema.create(engine, migrate_repository, version=1)
    db_schema = schema.ControlledSchema(engine, migrate_repository)
    if (migrate_repository.versions.latest != db_schema.version):
        config_arg = ''
        if (galaxy_config_file and (os.path.abspath(os.path.join(os.getcwd(), 'config', 'galaxy.ini')) != galaxy_config_file)):
            config_arg = ('    -c    %s' % galaxy_config_file.replace(os.path.abspath(os.getcwd()), '.'))
        raise...