code: def get_ffmpeg_exe():
      
      if 'FFMPEG_PATH' in os.environ:
          ffmpeg_exe = os.environ['FFMPEG_PATH']
      else:
          ffmpeg_exe = which('ffmpeg')
  
      if not ffmpeg_exe:
          if which('avconv'):
              raise FFmpegNormalizeError(
                  "avconv is not supported. "
                  "Please install ffmpeg from http://ffmpeg.org instead."
              )
          else:
              raise FFmpegNormalizeError(
                  "Could not find ffmpeg in your $PATH or $FFMPEG_PATH. "
                  "Please install ffmpeg from http://ffmpeg.org"
              )
  
      return ffmpeg_exe
docs: Return path to ffmpeg executable