diff --git a/Include/object.h b/Include/object.h
index ac72529..5a93000 100644
--- a/Include/object.h
+++ b/Include/object.h
@@ -135,6 +135,7 @@
 	object *(*nb_negative) FPROTO((object *));
 	object *(*nb_positive) FPROTO((object *));
 	object *(*nb_absolute) FPROTO((object *));
+	int (*nb_nonzero) FPROTO((object *));
 } number_methods;
 
 typedef struct {