[{'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 collect push notification tokens in order for us to be able to determine whether you are subscribed to push notifications. When you decide to unsubscribe from push notifications, such push notification tokens will be deleted from our database."}, {'role': 'assistant', 'content': 'This clause is fair. The privacy practices mentioned are: nan.'}]