def nodata(status_code):
    """Translate NODATA status codes from GnuPG to messages."""
    lookup = {'1': 'No armored data.', '2':
        'Expected a packet but did not find one.', '3':
        'Invalid packet found, this may indicate a non OpenPGP message.',
        '4': 'Signature expected but not found.'}
    for key, value in lookup.items():
        if str(status_code) == key:
            return value
