code: def mmGetMetricSequencesPredictedActiveCellsShared(self):
      
      self._mmComputeTransitionTraces()
  
      numSequencesForCell = defaultdict(lambda: 0)
  
      for predictedActiveCells in (
            self._mmData["predictedActiveCellsForSequence"].values()):
        for cell in predictedActiveCells:
          numSequencesForCell[cell] += 1
  
      return Metric(self,
                    "# sequences each predicted => active cells appears in",
                    numSequencesForCell.values())
docs: Metric for number of sequences each predicted => active cell appears in
  
      Note: This metric is flawed when it comes to high-order sequences.
  
      @return (Metric) metric