diff --git a/Lib/python/pycontainer.swg b/Lib/python/pycontainer.swg
index 06b76435c..b47601675 100644
--- a/Lib/python/pycontainer.swg
+++ b/Lib/python/pycontainer.swg
@@ -100,6 +100,8 @@ namespace swig {
 
 %fragment("PySequence_Base","header")
 {
+#include <functional>
+
 namespace std {
   template <>
   struct less <PyObject *>: public binary_function<PyObject *, PyObject *, bool>