code: def percent_point(self, U):
          
          self.check_fit()
  
          if not 0 < U < 1:
              raise ValueError('cdf value must be in [0,1]')
  
          return scipy.optimize.brentq(self.cumulative_distribution, -1000.0, 1000.0, args=(U))
docs: Given a cdf value, returns a value in original space.
  
          Args:
              U: `int` or `float` cdf value in [0,1]
  
          Returns:
              float: value in original space