code: def integral(requestContext, seriesList):
      results = []
      for series in seriesList:
          newValues = []
          current = 0.0
          for val in series:
              if val is None:
                  newValues.append(None)
              else:
                  current += val
                  newValues.append(current)
          newName = "integral(%s)" % series.name
          newSeries = TimeSeries(newName, series.start, series.end, series.step,
                                 newValues)
          newSeries.pathExpression = newName
          results.append(newSeries)
      return results