docs: def initialize(self, store):
          """Common initialization of handlers happens here. If additional
          initialization is required, this method must either be called with
          ``super`` or the child class must assign the ``store`` attribute and
          register itself with the store.
  
          """
          assert isinstance(store, stores.BaseStore)
          self.messages = Queue()
          self.store = store
          self.store.register(self)