code: def gyisland(self, dae):
          
          if self.system.Bus.islanded_buses:
              a = self.system.Bus.islanded_buses
              v = [self.system.Bus.n + item for item in a]
              dae.set_jac(Gy, 1e-6, a, a)
              dae.set_jac(Gy, 1e-6, v, v)
docs: Reset gy(x) for islanded buses and areas