diff --git a/debugging.py b/debugging.py
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--- /dev/null
+++ b/debugging.py
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+# -*- python -*-
+#
+# $Id: debugging.py,v 1.1 2011-08-31 18:25:07 wirawan Exp $
+#
+# Created: 20100909
+# Wirawan Purwanto
+#
+# Debugging tools for python
+#
+
+import re
+
+def fmtstr_find_missing_arguments(fmtstr, args):
+  """Finds what named arguments are not supplied."""
+  missing = {}
+  for kw1 in re.findall("%\([^)]+\)", fmtstr):
+    kw = kw1[2:-1]
+    if kw not in args:
+      missing[kw] = missing.get(kw,0) + 1
+  missing2 = missing.keys()
+  missing2.sort()
+  return missing2