diff --git a/verify_mnh_expand.py b/verify_mnh_expand.py
index 0c9e61b7b2db60cc24e3d74c22273f5c5ae2643c..854eb445dae328cfe1c4a8fc8b6a24c6ca0570c6 100755
--- a/verify_mnh_expand.py
+++ b/verify_mnh_expand.py
@@ -18,7 +18,7 @@ def verify_mnh_expand(path):
         the instruction will no be checked
       - one-line version of IF or WHERE statement are really on one line (no continuation line)
     """
-    lhschar = b'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890(:)%, \t'
+    lhschar = b'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890_(:)%, \t'
 
     if os.path.isdir(path):
         logging.info("Enters directory: " + path)