code: def tune(self, verbose=None):
          
          if not self._tune:
              return False
          else:
              self.w_tune.append(
                  abs(self.stochastic.last_value - self.stochastic.value))
              self.w = 2 * (sum(self.w_tune) / len(self.w_tune))
              return True
docs: Tuning initial slice width parameter