code: def diffusive_heat_transport(self):
          
          phi = np.deg2rad(self.lat)
          phi_stag = np.deg2rad(self.lat_bounds)
          D = self.param['D']
          T = np.squeeze(self.Ts)
          dTdphi = np.diff(T) / np.diff(phi)
          dTdphi = np.append(dTdphi, 0.)
          dTdphi = np.insert(dTdphi, 0, 0.)
          return (1E-15*-2*np.math.pi*np.cos(phi_stag)*const.a**2*D*dTdphi)
docs: Compute instantaneous diffusive heat transport in unit :math:`\\textrm{PW}`
          on the staggered grid (bounds) through calculating:
  
          .. math::
  
              H(\\varphi) = - 2 \pi R^2 cos(\\varphi) D \\frac{dT}{d\\varphi}
                          \\approx - 2 \pi R^2 cos(\\varphi) D \\frac{\Delta T}{\Delta \\varphi}
  
          :rtype: array of size ``np.size(self.lat_bounds)``
  
          THIS IS DEPRECATED AND WILL BE REMOVED IN THE FUTURE. Use the diagnostic
          ``heat_transport`` instead, which implements the same calculation.