Updated to flake8

youtube_dl/extractor/mujrozhlas.py

@@ -4,7 +4,6 @@ from __future__ import unicode_literals
 from .common import InfoExtractor
 from ..utils import (
     int_or_none,
-    remove_start,
     clean_html,
 )
 
@@ -48,6 +47,6 @@ class MujRozhlasIE(InfoExtractor):
             'url': audio_url,
             'title': title,
             'description': description,
-            'duration': int(duration),
+            'duration': int_or_none(duration),
             'vcodec': 'none',
         }