class NosVideoIE(InfoExtractor):
     _VALID_URL = r'https?://(?:www\.)?nosvideo\.com/' + \
-                 '(?:embed/|\?v=)(?P<id>[A-Za-z0-9]{12})/?'
+                 r'(?:embed/|\?v=)(?P<id>[A-Za-z0-9]{12})/?'
     _PLAYLIST_URL = 'http://nosvideo.com/xml/{xml_id:s}.xml'
     _FILE_DELETED_REGEX = r'<b>File Not Found</b>'
     _TEST = {
             'id': 'mu8fle7g7rpq',
             'ext': 'mp4',
             'title': 'big_buck_bunny_480p_surround-fix.avi.mp4',
-            'thumbnail': 're:^https?://.*\.jpg$',
+            'thumbnail': r're:^https?://.*\.jpg$',
         }
     }