[{'role': 'USR', 'utterance': 'Welcome. May I help you?'}
 {'role': 'SYS', 'utterance': 'Yes, I want an eye-shadow.'}
 {'role': 'USR', 'utterance': 'We have different colours of eye-shadow. May I know what colour you usually wear?'}
 {'role': 'SYS', 'utterance': "Purple. But today, I'm thinking of buying one in a bright colour."}
 {'role': 'USR', 'utterance': 'Yes, I see. How do you like this one?'}
 {'role': 'SYS', 'utterance': 'May I have a try?'}
 {'role': 'USR', 'utterance': 'Certainly.'}]
{'role': 'SYS', 'utterance': "It's still too dark. Any brighter colours?"}