diff --git a/Objects/bytearrayobject.c b/Objects/bytearrayobject.c
index d456678..a9c8ca6 100644
--- a/Objects/bytearrayobject.c
+++ b/Objects/bytearrayobject.c
@@ -400,11 +400,11 @@
     }
     else if (PySlice_Check(index)) {
         Py_ssize_t start, stop, step, slicelength, cur, i;
-        if (PySlice_GetIndicesEx(index,
-                                 PyByteArray_GET_SIZE(self),
-                                 &start, &stop, &step, &slicelength) < 0) {
+        if (PySlice_Unpack(index, &start, &stop, &step) < 0) {
             return NULL;
         }
+        slicelength = PySlice_AdjustIndices(PyByteArray_GET_SIZE(self),
+                                            &start, &stop, step);
 
         if (slicelength <= 0)
             return PyByteArray_FromStringAndSize("", 0);
@@ -630,11 +630,11 @@
         }
     }
     else if (PySlice_Check(index)) {
-        if (PySlice_GetIndicesEx(index,
-                                 PyByteArray_GET_SIZE(self),
-                                 &start, &stop, &step, &slicelen) < 0) {
+        if (PySlice_Unpack(index, &start, &stop, &step) < 0) {
             return -1;
         }
+        slicelen = PySlice_AdjustIndices(PyByteArray_GET_SIZE(self), &start,
+                                         &stop, step);
     }
     else {
         PyErr_Format(PyExc_TypeError,