diff --git a/libtorrent/bindings/python/src/session.cpp b/libtorrent/bindings/python/src/session.cpp
index 58fe76b3e..cf939d693 100755
--- a/libtorrent/bindings/python/src/session.cpp
+++ b/libtorrent/bindings/python/src/session.cpp
@@ -69,7 +69,7 @@ namespace
         : cb(callback)
       {}
 
-      boost::shared_ptr<torrent_plugin> operator()(torrent* t)
+      boost::shared_ptr<torrent_plugin> operator()(torrent* t, void*)
       {
           lock_gil lock;
           return extract<boost::shared_ptr<torrent_plugin> >(cb(ptr(t)))();