diff --git a/Python/Python-ast.c b/Python/Python-ast.c
index 8ba06ff..89c07cd 100644
--- a/Python/Python-ast.c
+++ b/Python/Python-ast.c
@@ -611,7 +611,7 @@
 
 static int obj2ast_string(PyObject* obj, PyObject** out, PyArena* arena)
 {
-    if (!PyUnicode_CheckExact(obj)) {
+    if (!PyUnicode_CheckExact(obj) && !PyBytes_CheckExact(obj)) {
         PyErr_SetString(PyExc_TypeError, "AST string must be of type str");
         return 1;
     }