docs: def imshow_z(data, name):
      """2D color plot of the quasiparticle weight as a function of interaction
         and doping"""
  
      zmes = pick_flat_z(data)
  
      plt.figure()
      plt.imshow(zmes.T, origin='lower', \
              extent=[data['doping'].min(), data['doping'].max(), \
              0, data['u_int'].max()], aspect=.16)
      plt.colorbar()
      plt.xlabel('$n$', fontsize=20)
      plt.ylabel('$U/D$', fontsize=20)
      plt.savefig(name+'_imshow.png', dpi=300, format='png',
              transparent=False, bbox_inches='tight', pad_inches=0.05)