diff --git a/Modules/arraymodule.c b/Modules/arraymodule.c
index d4221fe..64e0f17 100644
--- a/Modules/arraymodule.c
+++ b/Modules/arraymodule.c
@@ -2297,10 +2297,11 @@
         arrayobject* ar;
         int itemsize = self->ob_descr->itemsize;
 
-        if (PySlice_GetIndicesEx(item, Py_SIZE(self),
-                         &start, &stop, &step, &slicelength) < 0) {
+        if (PySlice_Unpack(item, &start, &stop, &step) < 0) {
             return NULL;
         }
+        slicelength = PySlice_AdjustIndices(Py_SIZE(self), &start, &stop,
+                                            step);
 
         if (slicelength <= 0) {
             return newarrayobject(&Arraytype, 0, self->ob_descr);
@@ -2368,11 +2369,11 @@
             return (*self->ob_descr->setitem)(self, i, value);
     }
     else if (PySlice_Check(item)) {
-        if (PySlice_GetIndicesEx(item,
-                                 Py_SIZE(self), &start, &stop,
-                                 &step, &slicelength) < 0) {
+        if (PySlice_Unpack(item, &start, &stop, &step) < 0) {
             return -1;
         }
+        slicelength = PySlice_AdjustIndices(Py_SIZE(self), &start, &stop,
+                                            step);
     }
     else {
         PyErr_SetString(PyExc_TypeError,