code: def Histograms(self, run, tag):
      
      accumulator = self.GetAccumulator(run)
      return accumulator.Histograms(tag)
docs: Retrieve the histogram events associated with a run and tag.
  
      Args:
        run: A string name of the run for which values are retrieved.
        tag: A string name of the tag for which values are retrieved.
  
      Raises:
        KeyError: If the run is not found, or the tag is not available for
          the given run.
  
      Returns:
        An array of `event_accumulator.HistogramEvents`.