Generators had their throw() method allowing string exceptions.  That's a
no-no.

Fixes issue #1147.  Need to fix 2.5 to raise a proper warning if a string
exception is passed in.
diff --git a/Objects/genobject.c b/Objects/genobject.c
index 14cc46b..551d9fd 100644
--- a/Objects/genobject.c
+++ b/Objects/genobject.c
@@ -252,10 +252,7 @@
 			Py_INCREF(typ);
 		}
 	}
-
-	/* Allow raising builtin string exceptions */
-
-	else if (!PyString_CheckExact(typ)) {
+	else {
 		/* Not something you can raise.  throw() fails. */
 		PyErr_Format(PyExc_TypeError,
 			     "exceptions must be classes, or instances, not %s",