YoutubeDL: If the logger is set call its `warning` method in `report_warning`

youtube_dl/YoutubeDL.py

@@ -370,6 +370,9 @@ class YoutubeDL(object):
         Print the message to stderr, it will be prefixed with 'WARNING:'
         If stderr is a tty file the 'WARNING:' will be colored
         '''
+        if self.params.get('logger') is not None:
+            self.params['logger'].warning(message)
+        else:
             if self._err_file.isatty() and os.name != 'nt':
                 _msg_header = '\033[0;33mWARNING:\033[0m'
             else: