How to use the stevedore.dispatch function in stevedore

def get_provisioning_manager():
    from stevedore import dispatch

    config = get_config()
    if config.get('PLUGIN_WHITELIST', ''):
        plugin_whitelist = config.get('PLUGIN_WHITELIST').split()
        mgr = dispatch.NameDispatchExtensionManager(
            namespace='pouta_blueprints.drivers.provisioning',
            check_func=lambda x: x.name in plugin_whitelist,
            invoke_on_load=True,
            invoke_args=(logger, get_config()),
        )
    else:
        mgr = dispatch.NameDispatchExtensionManager(
            namespace='pouta_blueprints.drivers.provisioning',
            check_func=lambda x: True,
            invoke_on_load=True,
            invoke_args=(logger, get_config()),
        )

    logger.debug('provisioning manager loaded, extensions: %s ' % mgr.names())

    return mgr

"""
    from stevedore import dispatch

    dynamic_config = get_dynamic_config()
    if dynamic_config.get('PLUGIN_WHITELIST'):
        plugin_whitelist = dynamic_config.get('PLUGIN_WHITELIST').split()
        mgr = dispatch.NameDispatchExtensionManager(
            namespace='pebbles.drivers.provisioning',
            check_func=lambda x: x.name in plugin_whitelist,
            invoke_on_load=True,
            invoke_args=(logger, dynamic_config),
        )
    else:
        # ahem, load all plugins if string is empty or not available?
        # is this wise? -jyrsa 2016-11-28
        mgr = dispatch.NameDispatchExtensionManager(
            namespace='pebbles.drivers.provisioning',
            check_func=lambda x: True,
            invoke_on_load=True,
            invoke_args=(logger, dynamic_config),
        )

    logger.debug('provisioning manager loaded, extensions: %s ' % mgr.names())

    return mgr

def get_provisioning_manager():
    from stevedore import dispatch

    config = get_config()
    if config.get('PLUGIN_WHITELIST', ''):
        plugin_whitelist = config.get('PLUGIN_WHITELIST').split()
        mgr = dispatch.NameDispatchExtensionManager(
            namespace='pouta_blueprints.drivers.provisioning',
            check_func=lambda x: x.name in plugin_whitelist,
            invoke_on_load=True,
            invoke_args=(logger, get_config()),
        )
    else:
        mgr = dispatch.NameDispatchExtensionManager(
            namespace='pouta_blueprints.drivers.provisioning',
            check_func=lambda x: True,
            invoke_on_load=True,
            invoke_args=(logger, get_config()),
        )

    logger.debug('provisioning manager loaded, extensions: %s ' % mgr.names())

    return mgr

def get_provisioning_manager():
    """ Gets a stevedore provisioning manager which controls access to all the
    possible drivers.

    Manager is used to call a method on one or more of the drivers.
    """
    from stevedore import dispatch

    dynamic_config = get_dynamic_config()
    if dynamic_config.get('PLUGIN_WHITELIST'):
        plugin_whitelist = dynamic_config.get('PLUGIN_WHITELIST').split()
        mgr = dispatch.NameDispatchExtensionManager(
            namespace='pebbles.drivers.provisioning',
            check_func=lambda x: x.name in plugin_whitelist,
            invoke_on_load=True,
            invoke_args=(logger, dynamic_config),
        )
    else:
        # ahem, load all plugins if string is empty or not available?
        # is this wise? -jyrsa 2016-11-28
        mgr = dispatch.NameDispatchExtensionManager(
            namespace='pebbles.drivers.provisioning',
            check_func=lambda x: True,
            invoke_on_load=True,
            invoke_args=(logger, dynamic_config),
        )

    logger.debug('provisioning manager loaded, extensions: %s ' % mgr.names())

def __init__(self, namespace="io.murano.extensions"):
        LOG.info('Loading extension plugins')
        self.namespace = namespace
        extension_manager = dispatch.EnabledExtensionManager(
            self.namespace,
            PluginLoader.is_plugin_enabled,
            on_load_failure_callback=PluginLoader._on_load_failure)
        self.packages = {}
        name_map = {}
        for ext in extension_manager.extensions:
            self.load_extension(ext, name_map)
        self.cleanup_duplicates(name_map)

def __init__(self):
        LOG.info('Loading package type plugins')
        extension_manager = dispatch.EnabledExtensionManager(
            NAMESPACE,
            self._is_plugin_enabled,
            on_load_failure_callback=self._on_load_failure)
        self.formats = {}
        for ext in extension_manager.extensions:
            self._load_plugin(ext)