Make type check work with subclasses
diff --git a/Modules/collectionsmodule.c b/Modules/collectionsmodule.c
index e49224d..368f0b6 100644
--- a/Modules/collectionsmodule.c
+++ b/Modules/collectionsmodule.c
@@ -587,7 +587,8 @@
PyObject *it1=NULL, *it2=NULL, *x, *y;
int i, b, vs, ws, minlen, cmp=-1;
- if (v->ob_type != &deque_type || w->ob_type != &deque_type) {
+ if (!PyObject_TypeCheck(v, &deque_type) ||
+ !PyObject_TypeCheck(w, &deque_type)) {
Py_INCREF(Py_NotImplemented);
return Py_NotImplemented;
}