code: def getRunNumber(g):
      
      if not g.cpars['hcam_server_on']:
          raise DriverError('getRunNumber error: servers are not active')
      url = g.cpars['hipercam_server'] + 'summary'
      response = urllib.request.urlopen(url, timeout=2)
      rs = ReadServer(response.read(), status_msg=True)
      if rs.ok:
          return rs.run
      else:
          raise DriverError('getRunNumber error: ' + str(rs.err))
docs: Polls the data server to find the current run number. Throws
      exceptions if it can't determine it.