code: def plot_densities(self, ax=None, **kwargs):
          
          ax, fig, plt = get_ax_fig_plt(ax)
  
          ax.grid(True)
          ax.set_xlabel('r [Bohr]')
          #ax.set_ylabel('density')
  
          for i, den_name in enumerate(["ae_core_density", "pseudo_core_density"]):
              rden = getattr(self, den_name)
              label = "$n_c$" if i == 1 else r"$\tilde{n}_c$"
              ax.plot(rden.mesh, rden.mesh * rden.values, label=label, lw=2)
  
          ax.legend(loc="best")
  
          return fig
docs: Plot the PAW densities.
  
          Args:
              ax: matplotlib :class:`Axes` or None if a new figure should be created.
  
          Returns:
              `matplotlib` figure