Renamed PyString to PyBytes
diff --git a/Modules/_sre.c b/Modules/_sre.c
index bfe4ae9..22aff76 100644
--- a/Modules/_sre.c
+++ b/Modules/_sre.c
@@ -1714,7 +1714,7 @@
     /* determine character size */
     size = PyObject_Size(string);
 
-    if (PyString_Check(string) || bytes == size)
+    if (PyBytes_Check(string) || bytes == size)
         charsize = 1;
 #if defined(HAVE_UNICODE)
     else if (bytes == (Py_ssize_t) (size * sizeof(Py_UNICODE)))