def prettify_fingerprint(fingerprint):
    """
    Returns the fingerprint in its common pretty form::
        XXXX XXXX XXXX XXXX XXXX  XXXX XXXX XXXX XXXX XXXX
    """
    if fingerprint is None:
        return 'NO FINGERPRINT'
    chunks = [fingerprint[i:i + 4] for i in range(0, 32, 4)]
    return '%s  %s' % (' '.join(chunks[0:4]), ' '.join(chunks[4:8]))