code: def get_available_transcript_languages(video_id):
      
      available_languages = VideoTranscript.objects.filter(
          video__edx_video_id=video_id
      ).values_list(
          'language_code', flat=True
      )
      return list(available_languages)
docs: Get available transcript languages
  
      Arguments:
          video_id(unicode): An id identifying the Video.
  
      Returns:
          A list containing transcript language codes for the Video.