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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def download_song(song_url, song_title):
 """ Download a song using youtube url and song title """


    outtmpl = song_title + '.%(ext)s'
    ydl_opts = {
        'format': 'bestaudio/best',
        'outtmpl': outtmpl,
        'postprocessors': [
            {'key': 'FFmpegExtractAudio','preferredcodec': 'mp3',
             'preferredquality': '192',
            },
            {'key': 'FFmpegMetadata'},
        ],
    }

    with youtube_dl.YoutubeDL(ydl_opts) as ydl:
        info_dict = ydl.extract_info(song_url, download=True)