code: def last_timestamp(self, sid, epoch=False):
          
          timestamp, value = self.last_datapoint(sid, epoch)
          return timestamp
docs: Get the theoretical last timestamp for a sensor
  
          Parameters
          ----------
          sid : str
              SensorID
          epoch : bool
              default False
              If True return as epoch
              If False return as pd.Timestamp
  
          Returns
          -------
          pd.Timestamp | int