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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 recommend(self, limit=10):
        '''
        Listup arms and expected value.

        Args:
            limit:      Length of the list.

        Returns:
            [Tuple(`Arms master id`, `expected value`)]
        '''
        expected_list = [(arm_id, beta_dist.expected_value()) for arm_id, beta_dist in self.__beta_dist_dict.items()]
        expected_list = sorted(expected_list, key=lambda x: x[1], reverse=True)
        return expected_list[:limit]