code: def pct_negative(self, threshold=0.0):
          
  
          return np.count_nonzero(self[self < threshold]) / self.count()
docs: Pct. of periods in which `self` is less than `threshold.`
  
          Parameters
          ----------
          threshold : {float, TSeries, pd.Series}, default 0.
  
          Returns
          -------
          float