diff --git a/imperative/python/src/numpy_dtypes.cpp b/imperative/python/src/numpy_dtypes.cpp
index 89310aea..1c195a87 100644
--- a/imperative/python/src/numpy_dtypes.cpp
+++ b/imperative/python/src/numpy_dtypes.cpp
@@ -117,6 +117,12 @@ struct _wrap {
         }
     }();
 
+    static PyObject* impl_py35(PyObject* self, PyObject* args) {
+        auto* arr = &PyTuple_GET_ITEM(args, 0);
+        auto size = PyTuple_GET_SIZE(args);
+        return impl(self, arr, size);
+    }
+
     static PyObject* impl(PyObject* self, PyObject*const* args, size_t nargs) {
         if (nargs != n_args) {
             PyErr_Format(PyExc_ValueError, "expected %lu arguments", n_args);
@@ -159,14 +165,21 @@ struct _wrap {
 
 } // anonymous namespace
 
+#ifdef METH_FASTCALL
+#define MGE_PY_INTERFACE(NAME, FUN) \
+    { #NAME, (PyCFunction)_wrap < &(FUN) > ::impl, METH_FASTCALL, nullptr }
+#else
+#define MGE_PY_INTERFACE(NAME, FUN) \
+    { #NAME, (PyCFunction)_wrap < &(FUN) > ::impl_py35, METH_VARARGS, nullptr }
+#endif
+
 void init_dtypes(py::module m) {
     static PyMethodDef method_defs[] = {
-        {"is_quantize",     (PyCFunction)_wrap<&_is_quantize>::impl,    METH_FASTCALL, nullptr},
-        {"get_scale",       (PyCFunction)_wrap<&_get_scale>::impl,      METH_FASTCALL, nullptr},
-        {"get_zero_point",  (PyCFunction)_wrap<&_get_zero_point>::impl, METH_FASTCALL, nullptr},
-        {"is_dtype_equal",  (PyCFunction)_wrap<&_is_dtype_equal>::impl, METH_FASTCALL, nullptr},
-        {nullptr, nullptr, 0, nullptr}
-    };
+            MGE_PY_INTERFACE(is_quantize, _is_quantize),
+            MGE_PY_INTERFACE(get_scale, _get_scale),
+            MGE_PY_INTERFACE(get_zero_point, _get_zero_point),
+            MGE_PY_INTERFACE(is_dtype_equal, _is_dtype_equal),
+            {nullptr, nullptr, 0, nullptr}};
     for (auto&& def: method_defs) {
         if (def.ml_meth != nullptr) {
             auto* func = PyCFunction_NewEx(&def, nullptr, nullptr);
@@ -176,4 +189,6 @@ void init_dtypes(py::module m) {
     }
 }
 
+#undef MGE_PY_INTERFACE
+
 } // namespace mgb
diff --git a/imperative/python/src/tensor.cpp b/imperative/python/src/tensor.cpp
index f924ddd9..3d5ae0bb 100644
--- a/imperative/python/src/tensor.cpp
+++ b/imperative/python/src/tensor.cpp
@@ -404,8 +404,6 @@ void TensorWrapper::setscalar() {
 }
 
 
-PyMethodDef apply_def{"apply", (PyCFunction)py_apply, METH_FASTCALL, nullptr};
-
 struct TensorWeakRef {
     std::weak_ptr<Tensor> wptr;
 
@@ -612,6 +610,24 @@ PyObject* get_device(PyObject* self, PyObject*const* args, size_t nargs) {
     }
 }
 
+#ifdef METH_FASTCALL
+#define MGE_PY_INTERFACE(NAME, FUNC) \
+    { #NAME, (PyCFunction)FUNC, METH_FASTCALL, nullptr }
+#else
+#define WRAP_FUNC_PY35(FUNC)                                \
+    PyObject* py35_##FUNC(PyObject* self, PyObject* args) { \
+        auto* arr = &PyTuple_GET_ITEM(args, 0);             \
+        auto size = PyTuple_GET_SIZE(args);                 \
+        return FUNC(self, arr, size);                       \
+    }
+WRAP_FUNC_PY35(py_apply);
+WRAP_FUNC_PY35(dtype_promotion);
+WRAP_FUNC_PY35(get_device);
+#undef WRAP_FUNC_PY35
+#define MGE_PY_INTERFACE(NAME, FUNC) \
+    { #NAME, (PyCFunction)py35_##FUNC, METH_VARARGS, nullptr }
+#endif
+
 void init_tensor(py::module m) {
     interpreter_for_py = interpreter::Interpreter::inst().create_channel();
 
@@ -643,11 +659,10 @@ void init_tensor(py::module m) {
         .def("__call__", &TensorWeakRef::operator());
 
     static PyMethodDef method_defs[] = {
-        {"apply", (PyCFunction)py_apply, METH_FASTCALL, nullptr},
-        {"dtype_promotion", (PyCFunction)dtype_promotion, METH_FASTCALL, nullptr},
-        {"get_device", (PyCFunction)get_device, METH_FASTCALL, nullptr},
-        {nullptr, nullptr, 0, nullptr}
-    };
+            MGE_PY_INTERFACE(apply, py_apply),
+            MGE_PY_INTERFACE(dtype_promotion, dtype_promotion),
+            MGE_PY_INTERFACE(get_device, get_device),
+            {nullptr, nullptr, 0, nullptr}};
     for (auto&& def: method_defs) {
         if (def.ml_meth != nullptr) {
             auto* func = PyCFunction_NewEx(&def, nullptr, nullptr);
@@ -698,4 +713,6 @@ void init_tensor(py::module m) {
 
 }
 
+#undef MGE_PY_INTERFACE
+
 } // namespace mgb::imperative::python