code: def plot_curves_z(data, name, title=None):
      
  
      plt.figure()
      for zet, c in zip(data['zeta'], data['doping']):
          plt.plot(data['u_int'], zet[:, 0], label='$n={}$'.format(str(c)))
      if title != None:
          plt.title(title)
      label_saves(name+'.png')
docs: Generates a simple plot of the quasiparticle weight decay curves given
         data object with doping setup