code: def computeSlop(self, step, divisor):
          
          bottom = step * math.floor(self.minValue / float(step) + EPSILON)
          top = bottom + step * divisor
  
          if top >= self.maxValue - EPSILON * step:
              return max(top - self.maxValue, self.minValue - bottom)
          else:
              return None
docs: Compute the slop that would result from step and divisor.
  
          Return the slop, or None if this combination can't cover the full
          range. See chooseStep() for the definition of "slop".