code: def _compute_dk_dy(self, y, n):
          r
          return 2.0**(1 - self.nu) / (scipy.special.gamma(self.nu)) * yn2Kn2Der(self.nu, y, n=n)
docs: r"""Evaluate the derivative of the outer form of the Matern kernel.
          
          Uses the general Leibniz rule to compute the n-th derivative of:
          
          .. math::
          
              f(y) = \frac{2^{1-\nu}}{\Gamma(\nu)} y^{\nu/2} K_\nu(y^{1/2})
          
          Parameters
          ----------
          y : :py:class:`Array`, (`M`,)
              `M` inputs to evaluate at.
          n : non-negative scalar int.
              Order of derivative to compute.
          
          Returns
          -------
          dk_dy : :py:class:`Array`, (`M`,)
              Specified derivative at specified locations.