docs: def plot_forward_models(self):
          """Plot the forward models (requires the forward models to be loaded)
          """
          pids_rho = self.assignments.get('forward_model', None)
          if pids_rho is None:
              raise Exception('you need to load the forward model first')
          fig, axes = plt.subplots(1, 2, figsize=(16 / 2.54, 8 / 2.54))
          ax = axes[0]
          self.plot.plot_elements_to_ax(
              pids_rho[0],
              ax=ax,
              plot_colorbar=True,
              cblabel=r'$|\rho| [\Omega m]$',
          )
  
          ax = axes[1]
          self.plot.plot_elements_to_ax(
              pids_rho[1],
              ax=ax,
              plot_colorbar=True,
              cblabel=r'$\phi [mrad]$',
          )
          fig.tight_layout()
          return fig, axes