[dhm] Remove unused import

youtube_dl/extractor/dhm.py

@@ -1,10 +1,7 @@
 from __future__ import unicode_literals
 
 from .common import InfoExtractor
-from ..utils import (
-    xpath_text,
-    parse_duration,
-)
+from ..utils import parse_duration
 
 
 class DHMIE(InfoExtractor):