338 static PyObject *
339 urj_pyc_set_instruction (urj_pychain_t *self, PyObject *args)
340 {
341     char *instname;
342     urj_part_t *part;
343     urj_chain_t *urc = self->urchain;
344     if (!PyArg_ParseTuple (args, "s", &instname))
when PyArg_ParseTuple() succeeds
taking False path
345         return NULL;
346     if (!urj_pyc_precheck (urc, UPRC_CBL))
when considering value == (int)0 from chain.c:346
taking True path
347         return NULL;
348 
349     part = urj_tap_chain_active_part (urc);
350     if (part == NULL)
351     {
352         PyErr_SetString (UrjtagError, _("No active part on chain"));
353         return NULL;
354     }
355     urj_part_set_instruction (part, instname);
356     return Py_BuildValue ("");
357 }
returning (PyObject*)NULL without setting an exception