[{'role': 'USR', 'utterance': 'What can I do for you today?'}
 {'role': 'SYS', 'utterance': 'I need to return a book.'}
 {'role': 'USR', 'utterance': 'Can I do anything else for you?'}
 {'role': 'SYS', 'utterance': 'I want to check this magazine out.'}
 {'role': 'USR', 'utterance': "We don't allow people to check out magazines."}
 {'role': 'SYS', 'utterance': 'Why not?'}
 {'role': 'USR', 'utterance': "It's just a policy of ours."}]
{'role': 'SYS', 'utterance': 'So what am I allowed to check out?'}