code: def percent_point(self, U):
          
          self.check_fit()
  
          return scipy.optimize.brentq(self._brentq_cdf(U), -1000.0, 1000.0)
docs: Given a cdf value, returns a value in original space.
  
          Args:
              U(numpy.array): cdf values in [0,1]
  
          Returns:
              numpy.array: value in original space