diff --git a/Objects/stringlib/string_format.h b/Objects/stringlib/string_format.h
index 2e9c7ef..be8e808 100644
--- a/Objects/stringlib/string_format.h
+++ b/Objects/stringlib/string_format.h
@@ -496,7 +496,7 @@
 #if PY_VERSION_HEX >= 0x03000000
     assert(PyUnicode_Check(result));
 #else
-    assert(PyBytes_Check(result) || PyUnicode_Check(result));
+    assert(PyString_Check(result) || PyUnicode_Check(result));
 
     /* Convert result to our type.  We could be str, and result could
        be unicode */
diff --git a/Objects/stringlib/stringdefs.h b/Objects/stringlib/stringdefs.h
index bdc3a29..daaa2e2 100644
--- a/Objects/stringlib/stringdefs.h
+++ b/Objects/stringlib/stringdefs.h
@@ -6,7 +6,7 @@
    compiled as unicode. */
 #define STRINGLIB_IS_UNICODE     0
 
-#define STRINGLIB_OBJECT         PyBytesObject
+#define STRINGLIB_OBJECT         PyStringObject
 #define STRINGLIB_CHAR           char
 #define STRINGLIB_TYPE_NAME      "string"
 #define STRINGLIB_PARSE_CODE     "S"
@@ -16,13 +16,13 @@
 #define STRINGLIB_TOUPPER        toupper
 #define STRINGLIB_TOLOWER        tolower
 #define STRINGLIB_FILL           memset
-#define STRINGLIB_STR            PyBytes_AS_STRING
-#define STRINGLIB_LEN            PyBytes_GET_SIZE
-#define STRINGLIB_NEW            PyBytes_FromStringAndSize
-#define STRINGLIB_RESIZE         _PyBytes_Resize
-#define STRINGLIB_CHECK          PyBytes_Check
+#define STRINGLIB_STR            PyString_AS_STRING
+#define STRINGLIB_LEN            PyString_GET_SIZE
+#define STRINGLIB_NEW            PyString_FromStringAndSize
+#define STRINGLIB_RESIZE         _PyString_Resize
+#define STRINGLIB_CHECK          PyString_Check
 #define STRINGLIB_CMP            memcmp
 #define STRINGLIB_TOSTR          PyObject_Str
-#define STRINGLIB_GROUPING       _PyBytes_InsertThousandsGrouping
+#define STRINGLIB_GROUPING       _PyString_InsertThousandsGrouping
 
 #endif /* !STRINGLIB_STRINGDEFS_H */