handle dict subclasses gracefully in PyArg_ValidateKeywordArguments
diff --git a/Python/getargs.c b/Python/getargs.c
index abf55ce..cf98699 100644
--- a/Python/getargs.c
+++ b/Python/getargs.c
@@ -1394,7 +1394,7 @@
 int
 PyArg_ValidateKeywordArguments(PyObject *kwargs)
 {
-    if (!PyDict_CheckExact(kwargs)) {
+    if (!PyDict_Check(kwargs)) {
         PyErr_BadInternalCall();
         return 0;
     }