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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 set(self, prefix, url, obj):
 """ Add an object into the cache """

        if not self.cache_dir:
            return

        filename = self._get_cache_file(prefix, url)

        try:
            os.makedirs(os.path.join(self.cache_dir, prefix))
        except OSError:
            pass

        with open(filename, 'wb') as file:
            pickle.dump(obj, file)