code: def histogram(values, bins=10, vrange=None, title="", c="g", corner=1, lines=True):
      
      fs, edges = np.histogram(values, bins=bins, range=vrange)
      pts = []
      for i in range(len(fs)):
          pts.append([(edges[i] + edges[i + 1]) / 2, fs[i]])
      return xyplot(pts, title, c, corner, lines)
docs: Build a 2D histogram from a list of values in n bins.
  
      Use *vrange* to restrict the range of the histogram.
  
      Use *corner* to assign its position:
          - 1, topleft,
          - 2, topright,
          - 3, bottomleft,
          - 4, bottomright.
  
      .. hint:: Example: |fitplanes.py|_