code: def _get_str_range(self, vals_stats):
          
          minmax = vals_stats[1] # stats minmax
          minval = self.fmtstr.format(minmax[0])
          maxval = self.fmtstr.format(minmax[1])
          return '{A} to {B:6>}'.format(A=minval, B=maxval)
docs: Return a string containing the range of values.