Renamed PyString to PyBytes
diff --git a/Objects/bytesobject.c b/Objects/bytesobject.c
index 98dc0f7..0a83725 100644
--- a/Objects/bytesobject.c
+++ b/Objects/bytesobject.c
@@ -728,7 +728,7 @@
         encoded = PyCodec_Encode(arg, encoding, errors);
         if (encoded == NULL)
             return -1;
-        assert(PyString_Check(encoded));
+        assert(PyBytes_Check(encoded));
         new = bytes_iconcat(self, encoded);
         Py_DECREF(encoded);
         if (new == NULL)
@@ -2895,7 +2895,7 @@
     /* XXX Shouldn't we use _getbuffer() on these items instead? */
     for (i = 0; i < n; i++) {
         PyObject *obj = items[i];
-        if (!PyByteArray_Check(obj) && !PyString_Check(obj)) {
+        if (!PyByteArray_Check(obj) && !PyBytes_Check(obj)) {
             PyErr_Format(PyExc_TypeError,
                          "can only join an iterable of bytes "
                          "(item %ld has type '%.100s')",
@@ -2924,7 +2924,7 @@
         if (PyByteArray_Check(obj))
            buf = PyByteArray_AS_STRING(obj);
         else
-           buf = PyString_AS_STRING(obj);
+           buf = PyBytes_AS_STRING(obj);
         if (i) {
             memcpy(dest, self->ob_bytes, mysize);
             dest += mysize;