When I do something like `@helpers.change_config('ckan.auth.default_group_or_org_permissions', 'manage_group')` a few lines below, I need to clear `new_authz.CONFIG_PERMISSIONS` so new calls to `new_authz.check_config_permissions` would re-read the config values and be affected by my change.

I used to explictly do `new_authz.CONFIG_PERMISSIONS = {}`, but using this method feels better, as I'm not messing up with internal constants. Maybe the method name is misleading. It not only clears the auth functions (that I don't care here), but also the `CONFIG_PERMISSIONS` (that's what I want).

Do you think creating a new `new_authz.clear_config_permissions_cache()` would be better?