diff --git a/util/GIL.h b/util/GIL.h
index 08c0a96..0b5b354 100644
--- a/util/GIL.h
+++ b/util/GIL.h
@@ -1,14 +1,18 @@
 #include <Python.h>
+#include <stdio.h>
+#include <iostream>
 struct PyLockGIL
 {
 
     PyLockGIL(): gstate(PyGILState_Ensure())
     {
+        std::cout << "construct GIL" << std::endl;
     }
 
     ~PyLockGIL()
     {
         PyGILState_Release(gstate);
+        std::cout << "destruct GIL" << std::endl;
     }
 
     PyLockGIL(const PyLockGIL&) = delete;