code: def str_numerator(self):
          
          if not self.undefined:
              return None
          unit_numerator, unit = self._unit_class(self.numerator).auto
          formatter = '%d' if unit_numerator == self.numerator else '%0.2f'
          numerator = locale.format(formatter, unit_numerator, grouping=True)
          return '{0} {1}'.format(numerator, unit)
docs: Returns the numerator with formatting.