diff --git a/scripts/docs-headings.py b/scripts/docs-headings.py
--- a/scripts/docs-headings.py
+++ b/scripts/docs-headings.py
@@ -35,6 +35,7 @@ headermatch = re.compile(r'''\n*(.+)\n([
 def main():
     filenames = subprocess.check_output(['hg', 'loc', 'set:**.rst+kallithea/i18n/how_to']).splitlines()
     for fn in filenames:
+        fn = fn.decode()
         print('processing %s' % fn)
         s = open(fn).read()