Add Str, a subclass of str.
diff --git a/Modules/xxmodule.c b/Modules/xxmodule.c
index 501de86..c312d2e 100644
--- a/Modules/xxmodule.c
+++ b/Modules/xxmodule.c
@@ -211,6 +211,59 @@
 }
 
 
+/* ---------- */
+
+static PyTypeObject Str_Type = {
+	/* The ob_type field must be initialized in the module init function
+	 * to be portable to Windows without using C++. */
+	PyObject_HEAD_INIT(NULL)
+	0,			/*ob_size*/
+	"xxmodule.Str",		/*tp_name*/
+	0,			/*tp_basicsize*/
+	0,			/*tp_itemsize*/
+	/* methods */
+	0,			/*tp_dealloc*/
+	0,			/*tp_print*/
+	0,			/*tp_getattr*/
+	0,			/*tp_setattr*/
+	0,			/*tp_compare*/
+	0,			/*tp_repr*/
+	0,			/*tp_as_number*/
+	0,			/*tp_as_sequence*/
+	0,			/*tp_as_mapping*/
+	0,			/*tp_hash*/
+	0,			/*tp_call*/
+	0,			/*tp_str*/
+	0,			/*tp_getattro*/
+	0,			/*tp_setattro*/
+	0,			/*tp_as_buffer*/
+	Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE, /*tp_flags*/
+	0,			/*tp_doc*/
+	0,			/*tp_traverse*/
+	0,			/*tp_clear*/
+	0,			/*tp_richcompare*/
+	0,			/*tp_weaklistoffset*/
+	0,			/*tp_iter*/
+	0,			/*tp_iternext*/
+	0,			/*tp_methods*/
+	0,			/*tp_members*/
+	0,			/*tp_getset*/
+	&PyString_Type,		/*tp_base*/
+	0,			/*tp_dict*/
+	0,			/*tp_descr_get*/
+	0,			/*tp_descr_set*/
+	0,			/*tp_dictoffset*/
+	0,			/*tp_init*/
+	0,			/*tp_alloc*/
+	0,			/*tp_new*/
+	0,			/*tp_free*/
+	0,			/*tp_is_gc*/
+};
+
+
+/* ---------- */
+
+
 /* List of functions defined in the module */
 
 static PyMethodDef xx_methods[] = {
@@ -252,4 +305,9 @@
 	}
 	Py_INCREF(ErrorObject);
 	PyModule_AddObject(m, "error", ErrorObject);
+
+	/* Add Str */
+	if (PyType_Ready(&Str_Type) < 0)
+		return;
+	PyModule_AddObject(m, "Str", (PyObject *)&Str_Type);
 }