List neutron extensions.

    :param request: django request object

def list_extensions(request):
    """List neutron extensions.

    :param request: django request object
    """
    neutron_api = neutronclient(request)
    try:
        extensions_list = neutron_api.list_extensions()
    except exceptions.ServiceCatalogException:
        return {}
    if 'extensions' in extensions_list:
        return tuple(extensions_list['extensions'])
    else:
        return ()