code: def add_age_defaults(self):
          
          if isinstance(self.magic_dataframe, cb.MagicDataFrame):
              for col in ['age', 'age_unit']:
                  if col not in self.grid.col_labels:
                      self.grid.add_col(col)
              for level in ['locations', 'sites', 'samples', 'specimens']:
                  if level in self.contribution.tables:
                      if level[:-1] not in self.grid.col_labels:
                          self.grid.add_col(level[:-1])
docs: Add columns as needed:
          age, age_unit, specimen, sample, site, location.