message: Fix regression in binding of set_gradient
diff: @@ -465,12 +465,13 @@ py::class_<Array> bind(py::module &m, const char *name) {
  m.def("set_requires_gradient",
  [](Array &a, bool value) { set_requires_gradient(a, value); },
  "array"_a, "value"_a = true);
  + m.def("detach", [](const Matrix4fD &a) { return eval(detach(a)); });
  m.def("gradient", [](Array &a) -> Detached { return gradient(a); });
  m.def("gradient_index", [](Array &a) { return gradient_index(a); });
  m.def("set_gradient",
  - [](Array &a, const Detached &g, bool backward) { set_gradient(a, g, backward); },
  + [](Array &a, const Array &g, bool backward) { set_gradient(a, detach(g), backward); },
  "array"_a, "gradient"_a, "backward"_a = true);
  m.def("graphviz", [](const Array &a) { return graphviz(a); });
  