code: def scheduleMeasurement(self, measurementId, duration, start):
          
          # TODO subtract 1s from start and format
          results = {}
          for device in self.getDevices(RecordingDeviceStatus.INITIALISED.name):
              logger.info('Sending measurement ' + measurementId + ' to ' + device.payload['serviceURL'])
              try:
                  resp = self.httpclient.put(device.payload['serviceURL'] + '/measurements/' + measurementId,
                                             json={'duration': duration, 'at': start.strftime(DATETIME_FORMAT)})
                  logger.info('Response for ' + measurementId + ' from ' + device.payload['serviceURL'] + ' is ' +
                              str(resp.status_code))
                  results[device] = resp.status_code
              except Exception as e:
                  logger.exception(e)
                  results[device] = 500
          return results
docs: Schedules the requested measurement session with all INITIALISED devices.
          :param measurementId:
          :param duration:
          :param start:
          :return: a dict of device vs status.