diff --git a/Objects/unicodeobject.c b/Objects/unicodeobject.c
index bfd5c88..342e7ee 100644
--- a/Objects/unicodeobject.c
+++ b/Objects/unicodeobject.c
@@ -658,7 +658,7 @@ unicode_result_ready(PyObject *unicode)
     if (length == 1) {
         int kind = PyUnicode_KIND(unicode);
         if (kind == PyUnicode_1BYTE_KIND) {
-            Py_UCS1 *data = PyUnicode_1BYTE_DATA(unicode);
+            const Py_UCS1 *data = PyUnicode_1BYTE_DATA(unicode);
             Py_UCS1 ch = data[0];
             struct _Py_unicode_state *state = get_unicode_state();
             PyObject *latin1_char = state->latin1[ch];