diff --git a/Python/thread.c b/Python/thread.c
index bac0e69..1276103 100644
--- a/Python/thread.c
+++ b/Python/thread.c
@@ -6,7 +6,7 @@
    Stuff shared by all thread_*.h files is collected here. */
 
 #include "Python.h"
-#include "pycore_pystate.h"
+#include "pycore_pystate.h"   // _PyInterpreterState_GET()
 
 #ifndef _POSIX_THREADS
 /* This means pthreads are not implemented in libc headers, hence the macro