def _get_editable(self, request):
        """
        Get the dictionary of editable settings for a given request. Settings
        are fetched from the database once per request and then stored in
        ``_editable_caches``, a WeakKeyDictionary that will automatically
        discard each entry when no more references to the request exist.
        """
        try:
            editable_settings = self._editable_caches[request]
        except KeyError:
            editable_settings = self._editable_caches[request] = self._load()
        return editable_settings