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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 get_tempo(artist, title):
    "gets the tempo for a song"
    results = song.search(artist=artist, title=title, results=1, buckets=['audio_summary'])
    if len(results) > 0:
        return results[0].audio_summary['tempo']
    else:
        return None