Plugin cleanup and tweaks

plugins/youtube_download/yt_dlp/extractor/nick.py

@@ -1,7 +1,3 @@
-# coding: utf-8
-from __future__ import unicode_literals
-
-
 from .mtv import MTVServicesInfoExtractor
 from ..utils import update_url_query
 
@@ -192,7 +188,7 @@ class NickDeIE(MTVServicesInfoExtractor):
         return self._remove_template_parameter(config['feedWithQueryParams'])
 
 
-class NickNightIE(NickDeIE):
+class NickNightIE(NickDeIE):  # XXX: Do not subclass from concrete IE
     IE_NAME = 'nicknight'
     _VALID_URL = r'https?://(?:www\.)(?P<host>nicknight\.(?:de|at|tv))/(?:playlist|shows)/(?:[^/]+/)*(?P<id>[^/?#&]+)'
     _TESTS = [{