text: #!/usr/bin/env python
  import numpy as np
  from basic_units import cm, inch
  import matplotlib.pyplot as plt
  
  
  N = 5
  menMeans = (150*cm, 160*cm, 146*cm, 172*cm, 155*cm)
  menStd = (20*cm,  30*cm,  32*cm,  10*cm,  20*cm)
  
  fig, ax = plt.subplots()
  
  ind = np.arange(N)    # the x locations for the groups
  width = 0.35         # the width of the bars
  p1 = ax.bar(ind, menMeans, width, color='r', bottom=0*cm, yerr=menStd)
  
  
  womenMeans = (145*cm, 149*cm, 172*cm, 165*cm, 200*cm)
  womenStd = (30*cm, 25*cm, 20*cm, 31*cm, 22*cm)
  p2 = ax.bar(ind+width, womenMeans, width, color='y', bottom=0*cm, yerr=womenStd)
  
  ax.set_title('Scores by group and gender')
  ax.set_xticks(ind+width)
  ax.set_xticklabels(('G1', 'G2', 'G3', 'G4', 'G5'))
  
  ax.legend((p1[0], p2[0]), ('Men', 'Women'))
  ax.yaxis.set_units(inch)
  ax.autoscale_view()
  
  #plt.savefig('barchart_demo')
  plt.show()
  