docs: def is_year(self):
          """Determine if a data record is of type YEAR."""
          dt = DATA_TYPES['year']
          if dt['min'] and dt['max']:
              if type(self.data) is dt['type'] and dt['min'] < self.data < dt['max']:
                  self.type = 'year'.upper()
                  self.len = None
                  return True