code: def corner_observed(self, **kwargs):
          
          tot_mags = []
          names = []
          truths = []
          rng = []
          for n in self.obs.get_obs_nodes():
              labels = [l.label for l in n.get_model_nodes()]
              band = n.band
              mags = [self.samples['{}_mag_{}'.format(band, l)] for l in labels]
              tot_mag = addmags(*mags)
  
              if n.relative:
                  name = '{} $\Delta${}'.format(n.instrument, n.band)
                  ref = n.reference
                  if ref is None:
                      continue
                  ref_labels = [l.label for l in ref.get_model_nodes()]
                  ref_mags = [self.samples['{}_mag_{}'.format(band, l)] for l in ref_labels]
                  tot_ref_mag = addmags(*ref_mags)
                  tot_mags.append(tot_mag - tot_ref_mag)
                  truths.append(n.value[0] - ref.value[0])
              else:
                  name = '{} {}'.format(n.instrument, n.band)
                  tot_mags.append(tot_mag)
                  truths.append(n.value[0])
  
              names.append(name)
              rng.append((min(truths[-1], np.percentile(tot_mags[-1],0.5)),
                          max(truths[-1], np.percentile(tot_mags[-1],99.5))))
          tot_mags = np.array(tot_mags).T
  
  
          return corner.corner(tot_mags, labels=names, truths=truths, range=rng, **kwargs)
docs: Makes corner plot for each observed node magnitude