static PyObject *
deque_repr(PyObject *deque)
{
    PyObject *aslist, *result;
    ...
    aslist = PySequence_List(deque);
    ...
    if (((dequeobject *)deque)->maxlen >= 0)
        result = PyUnicode_FromFormat("%s(%R, maxlen=%zd)",
                                      _PyType_Name(Py_TYPE(deque)), aslist,
                                      ((dequeobject *)deque)->maxlen);
    else
        result = PyUnicode_FromFormat("%s(%R)",
                                      _PyType_Name(Py_TYPE(deque)), aslist);
    ...
    return result;
}