code: def plot_model(self, proj, ax):
          
          x, y = proj
          evaluated_model = self.ig._eval_model()
          y_vals = getattr(evaluated_model, y.name)
          x_vals = self.ig._x_grid[x]
          plot = ax.errorbar(x_vals, y_vals, xerr=0, yerr=0, c='red')
          return plot
docs: Plots the model proposed for the projection proj on ax.