code: def ttl(self):
          
  
          # result is self ts
          result = getattr(self, Annotation.__TS, None)
          # if result is not None
          if result is not None:
              # result is now - result
              now = time()
              result = result - now
  
          return result
docs: Get actual ttl in seconds.
  
          :return: actual ttl.
          :rtype: float