--- a/py_ext/PythonFileCTNMixin.py	Tue Oct 09 11:43:39 2018 +0300
+++ b/py_ext/PythonFileCTNMixin.py	Tue Oct 09 11:56:45 2018 +0300
@@ -63,8 +63,8 @@
                 'xmlns="http://www.w3.org/2001/XMLSchema"',
                 'xmlns:xhtml="http://www.w3.org/1999/xhtml"')
             for cre, repl in [
-                    (re.compile("(?<!<xhtml:p>)(?:<!\[CDATA\[)"), "<xhtml:p><![CDATA["),
-                    (re.compile("(?:]]>)(?!</xhtml:p>)"), "]]></xhtml:p>")]:
+                    (re.compile(r"(?<!<xhtml:p>)(?:<!\[CDATA\[)"), "<xhtml:p><![CDATA["),
+                    (re.compile(r"(?:]]>)(?!</xhtml:p>)"), "]]></xhtml:p>")]:
                 pythonfile_xml = cre.sub(repl, pythonfile_xml)
 
             try: