code: def roundTo(self):
          
          if self._roundTo is None:
              min_val = max(self.minimum(), 1)
              max_val = max(self.maximum(), 1)
              max_labels = self.maximumLabelCount()
              
              return int(round((max_val - min_val) / float(max_labels)))
              
          return self._roundTo
docs: Returns the number that this should round the default values to.
          
          :return     <int>