code: def _validate_params(self):
          
          if self.expectile >= 1 or self.expectile <= 0:
              raise ValueError('expectile must be in (0,1), but found {}'.format(self.expectile))
          self.distribution = NormalDist(scale=self.scale)
          super(ExpectileGAM, self)._validate_params()
docs: method to sanitize model parameters
  
          Parameters
          ---------
          None
  
          Returns
          -------
          None