[{'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: In most cases, once we detect that all recipients have viewed a message, we automatically delete it from our servers. And again in most cases, the Services are programmed to delete the message from the recipients' device as well. There is, however, an exception to this general rule: Infinity timer: Senders can choose an infinity timer option to prevent deleting their messages from recipient's device."}, {'role': 'assistant', 'content': 'This clause is fair. The privacy practices mentioned are: nan.'}]