Get rid of more uses of string and use unicode
diff --git a/Objects/frameobject.c b/Objects/frameobject.c
index 7ec7ed5..cf41ddd 100644
--- a/Objects/frameobject.c
+++ b/Objects/frameobject.c
@@ -721,7 +721,7 @@
 	for (j = nmap; --j >= 0; ) {
 		PyObject *key = PyTuple_GET_ITEM(map, j);
 		PyObject *value = values[j];
-		assert(PyString_Check(key)/*XXX this should go*/ || PyUnicode_Check(key));
+		assert(PyUnicode_Check(key));
 		if (deref) {
 			assert(PyCell_Check(value));
 			value = PyCell_GET(value);