code: def get(self, key):
          
  
          if not key in self._actions:
              return None
          if not key in self._cache:
              self._cache[key] = self._actions[key]()
  
          return self._cache[key]
docs: Executes the callable registered at the specified key and returns
              its value. Subsequent queries are cached internally.
  
              `key`
                  String key for a previously stored callable.