code: def mostDeviant(requestContext, seriesList, n):
      
  
      deviants = []
      for series in seriesList:
          mean = safeAvg(series)
          if mean is None:
              continue
          square_sum = sum([(value - mean) ** 2 for value in series
                            if value is not None])
          sigma = safeDiv(square_sum, safeLen(series))
          if sigma is None:
              continue
          deviants.append((sigma, series))
      return [series for sig, series in sorted(deviants,  # sort by sigma
                                               key=itemgetter(0),
                                               reverse=True)][:n]
docs: Takes one metric or a wildcard seriesList followed by an integer N.
      Draws the N most deviant metrics.
      To find the deviants, the standard deviation (sigma) of each series
      is taken and ranked. The top N standard deviations are returned.
  
      Example::
  
          &target=mostDeviant(server*.instance*.memory.free, 5)
  
      Draws the 5 instances furthest from the average memory free.