code: def split_six(series=None):
      
      if pd is None:
          raise ImportError('The Pandas package is required'
                            ' for this functionality')
      if np is None:
          raise ImportError('The NumPy package is required'
                            ' for this functionality')
  
      def base(x):
          if x > 0:
              base = pow(10, math.floor(math.log10(x)))
              return round(x/base)*base
          else:
              return 0
  
      quants = [0, 50, 75, 85, 90]
      # Some weirdness in series quantiles a la 0.13.
      arr = series.values
      return [base(np.percentile(arr, x)) for x in quants]
docs: Given a Pandas Series, get a domain of values from zero to the 90% quantile
      rounded to the nearest order-of-magnitude integer. For example, 2100 is
      rounded to 2000, 2790 to 3000.
  
      Parameters
      ----------
      series: Pandas series, default None
  
      Returns
      -------
      list