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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 refresh(self, item):
 """ Forces a refresh of a cached item. :param item: Client name. :type item: unicode | str :return: Items in the cache. :rtype: DockerHostItemCache.item_class """

        client = self._clients[item].get_client()
        self[item] = val = self.item_class(client)
        return val