diff --git a/clean_commonscat.py b/clean_commonscat.py
index 030cd6f..ea3ae80 100644
--- a/clean_commonscat.py
+++ b/clean_commonscat.py
@@ -40,7 +40,9 @@ def setup(self):
         ns = '|'.join(self.site.namespaces[14])
         self.empty_sectionR = re.compile(
             r'\s*\n==+ *Externí odkazy *==+ *\n\s*'
-            fr'(?:^==|^\{\{(?:{templates})|^\[\[(?:{ns}):)', flags=re.M)
+            r'^(?:==|\{\{(?:{templates})|\[\[(?:{ns}):)'
+            .format(templates=templates, ns=ns),
+            flags=re.M)
 
     def treat_page(self):  # todo: treat_page_and_item
         page = self.current_page