docs: def to_pandas(self):
          """Convert record to pandas.DataFrame"""
          agedepthdf = pd.DataFrame(self.age, index=self.data.depth)
          agedepthdf.columns = list(range(self.n_members()))
          out = (agedepthdf.join(self.data.set_index('depth'))
                 .reset_index()
                 .melt(id_vars=self.data.columns.values, var_name='mciter', value_name='age'))
          out['mciter'] = pd.to_numeric(out.loc[:, 'mciter'])
          if self.n_members() == 1:
              out = out.drop('mciter', axis=1)
          return out