code: def xformatter(self, x, pos):
          " x-axis formatter "
          if self.use_dates:
              return self.__date_format(x)
          else:
              return self.__format(x, type='x'f xformatter(self, x, pos):
          " x-axis formatter "
          if self.use_dates:
              return self.__date_format(x)
          else:
              return self.__format(x, type='x')
docs: x-axis formatter