human
I wrote the below code

    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...

What's a good function header?

=====
Here's a good function header?
assistant
#Here's a good function header.

def create_or_verify_database(url, galaxy_config_file, engine_options={}, app=None):