Correct bug

src/view/mpl/Mpl.cpp

@@ -172,7 +172,7 @@ void Mpl::close(const PythonObject& figure) throw (Error) {
 	MplLock lock;
 
 	// Create matplotlib figure object
-	auto args = bp::make_tuple(figure);
+	auto args = bp::make_tuple(figure());
 	try {
 		m_PyPlot.attr("close")(*args);
 	} catch (...) {