code: def stemify(x, y):
  
      
  
      xx = numpy.zeros(3 * len(x), dtype=float)
      yy = numpy.zeros(3 * len(y), dtype=float)
      xx[0::3], xx[1::3], xx[2::3] = x, x, x
      yy[1::3] = y
      return xx, yy
docs: Stemify a curve (x, y). This is useful for filling histograms manually.