[{'role': 'user', 'content': "Analyze the following clause from a privacy policy and determine if it's fair or unfair. Also identify any privacy practices mentioned: We encourage you to promptly update your PII if it changes. You may ask to have the information on your account deleted or removed; however, because we keep track of past transactions, you cannot delete information associated with past transactions. In addition, it may be impossible to completely delete your information without some residual information because of backups."}, {'role': 'assistant', 'content': 'This clause is fair. The privacy practices mentioned are: nan.'}]