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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 get_closed_indices(self):
 """ Get all closed indices. """

        state = self.conn.cluster.state()
        status = self.status()

        indices_metadata = set(state['metadata']['indices'].keys())
        indices_status = set(status['indices'].keys())

        return indices_metadata.difference(indices_status)