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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 clear_cached_endpoints(self, prefix=None):
 """ Invalidate all cached endpoints, meta included Loop over all meta endpoints to generate all cache key the invalidate each of them. Doing it this way will prevent the app not finding keys as the user may change its prefixes Meta endpoint will be updated upon next call. :param: prefix the prefix for the cache key (default is cache_prefix) """

        prefix = prefix if prefix is not None else self.cache_prefix
        for endpoint in self.app.op.values():
            cache_key = '%s:app:%s' % (prefix, endpoint.url)
            self.cache.invalidate(cache_key)
        self.cache.invalidate('%s:app:meta_swagger_url' % self.cache_prefix)
        self.app = None