PyArg_ParseTupleAndKeywords and optional unicode arguments

[Roger Upole]

I'm having a problem with an extension module using
PyArg_ParseTupleAndKeywords with 2.3.2.
Distilled down:

PyObject *wtf(PyObject *self, PyObject *args, PyObject *kwargs)
{
WCHAR *dummy1=NULL;
WCHAR *dummy2=NULL;
WCHAR *dummy3=NULL;
static char *dummyelements[]={"dummy1","dummy2","dummy3",0};
if (!PyArg_ParseTupleAndKeywords(args, kwargs, "|uuu:wtf", dummyelements,
&dummy1, &dummy2, &dummy3))
return NULL;
Py_INCREF(Py_None);
return Py_None;
}

wtf(dummy1=u'xxxxxx',dummy3=u'dummy3') Traceback (most recent call last):
File "<stdin>", line 1, in ?
TypeError: wtf() argument 2 impossible<bad format char>
[17300 refs]

Anybody seen this before, or is this a known problem, or am I just missing
something obvious ?
Any help greatly appreciated.
Roger