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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 upload_path(instance, filename):
    '''
        Sanitize the user-provided file name, add timestamp for uniqness.
    '''

    filename = filename.replace(" ", "_")
    filename = unicodedata.normalize('NFKD', filename).lower()
    return os.path.join(str(timezone.now().date().isoformat()), filename)