code: def plot_xbt(fignum, XB, T, e, b):
      
      plt.figure(num=fignum)
      plt.clf()
      if not isServer:
          plt.figtext(.02, .01, version_num)
      plt.xlabel('Field (T)')
      plt.ylabel('Susceptibility (m^3/kg)')
      k = 0
      B, X = [], []
      for xb in XB:
          X.append(xb[0])
          B.append(xb[1])
      plt.plot(B, X)
      plt.legend(['%i' % (int(T)) + ' K'])
      plt.title(e + ': f = ' + '%i' % (int(f)) + ' Hz')
docs: function to plot series of chi measurements as a function of temperature, holding field constant and varying frequency