Function IsNamedtuple

tensorflow/python/util/util.cc:910–959

}

PyObject* IsNamedtuple(PyObject* o, bool strict) {
  // Must be subclass of tuple
  if (!PyTuple_Check(o)) {
    Py_RETURN_FALSE;
  }

  // If strict, o.__class__.__base__ must be tuple
  if (strict) {
    PyObject* klass = PyObject_GetAttrString(o, "__class__");
    if (klass == nullptr) return nullptr;
    PyObject* base = PyObject_GetAttrString(klass, "__base__");
    Py_DECREF(klass);
    if (base == nullptr) return nullptr;

    const PyTypeObject* base_type = reinterpret_cast<PyTypeObject*>(base);
    // built-in object types are singletons
    bool tuple_base = base_type == &PyTuple_Type;
    Py_DECREF(base);
    if (!tuple_base) {
      Py_RETURN_FALSE;
    }
  }

  // o must have attribute '_fields' and every element in
  // '_fields' must be a string.
  int has_fields = PyObject_HasAttrString(o, "_fields");
  if (!has_fields) {
    Py_RETURN_FALSE;
  }

  Safe_PyObjectPtr fields = make_safe(PyObject_GetAttrString(o, "_fields"));
  int is_instance = IsInstanceOfRegisteredType(fields.get(), "Sequence");
  if (is_instance == 0) {
    Py_RETURN_FALSE;
  } else if (is_instance == -1) {
    return nullptr;
  }

  Safe_PyObjectPtr seq = make_safe(PySequence_Fast(fields.get(), ""));
  const Py_ssize_t s = PySequence_Fast_GET_SIZE(seq.get());
  for (Py_ssize_t i = 0; i < s; ++i) {
    // PySequence_Fast_GET_ITEM returns borrowed ref
    PyObject* elem = PySequence_Fast_GET_ITEM(seq.get(), i);
    if (!IsString(elem)) {
      Py_RETURN_FALSE;
    }
  }

  Py_RETURN_TRUE;
}

PyObject* SameNamedtuples(PyObject* o1, PyObject* o2) {
  Safe_PyObjectPtr f1 = make_safe(PyObject_GetAttrString(o1, "_fields"));