code: def _update(self, datapoints):
          
          if len(datapoints) == 1:
              timestamp, value = datapoints[0]
              whisper.update(self.path, value, timestamp)
          else:
              whisper.update_many(self.path, datapoints)
docs: This method store in the datapoints in the current database.
  
              :datapoints: is a list of tupple with the epoch timestamp and value
                   [(1368977629,10)]