Plugin cleanup and tweaks

plugins/youtube_download/yt_dlp/extractor/cmt.py

@@ -1,11 +1,9 @@
-from __future__ import unicode_literals
-
 from .mtv import MTVIE
 
 # TODO Remove - Reason: Outdated Site
 
 
-class CMTIE(MTVIE):
+class CMTIE(MTVIE):  # XXX: Do not subclass from concrete IE
     IE_NAME = 'cmt.com'
     _VALID_URL = r'https?://(?:www\.)?cmt\.com/(?:videos|shows|(?:full-)?episodes|video-clips)/(?P<id>[^/]+)'