code: def scaled_euclid_dist(self, X, X2):  # pragma: no cover
          
          warnings.warn('scaled_euclid_dist is deprecated and will be removed '
                        'in GPflow version 1.4.0. For stationary kernels, '
                        'define K_r(r) instead.',
                        DeprecationWarning)
          r2 = self.scaled_square_dist(X, X2)
          return self._clipped_sqrt(r2)
docs: Returns |(X - X2ᵀ)/lengthscales| (L2-norm).