add fitness blender

yt_dlp/extractor/_extractors.py

@@ -653,6 +653,7 @@ from .filmon import (
 )
 from .filmweb import FilmwebIE
 from .firsttv import FirstTVIE
+from .fitnessblender import FitnessBlenderIE
 from .fivetv import FiveTVIE
 from .flextv import FlexTVIE
 from .flickr import FlickrIE