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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _reset(self):
 """ This method is for use by tests only! """

        self.bundles = AttrDict()
        self._bundles = _DeferredBundleFunctionsStore()
        self.babel_bundle = None
        self.env = None
        self.extensions = AttrDict()
        self.services = AttrDict()

        self._deferred_functions = []
        self._initialized = False
        self._models_initialized = False
        self._services_initialized = False
        self._services_registry = {}
        self._shell_ctx = {}