That one was a mistake.
diff --git a/Objects/unicodeobject.c b/Objects/unicodeobject.c
index 9ebefd0..a503d15 100644
--- a/Objects/unicodeobject.c
+++ b/Objects/unicodeobject.c
@@ -6380,7 +6380,7 @@
     /* Order is according to common usage: often used methods should
        appear first, since lookup is done sequentially. */
 
-    {"encode",  unicode_encode, METH_VARARGS, encode__doc__},
+    {"encode", (PyCFunction) unicode_encode, METH_VARARGS, encode__doc__},
     {"replace", (PyCFunction) unicode_replace, METH_VARARGS, replace__doc__},
     {"split", (PyCFunction) unicode_split, METH_VARARGS, split__doc__},
     {"rsplit", (PyCFunction) unicode_rsplit, METH_VARARGS, rsplit__doc__},