@staticmethod
def _parse_unit(raw_unit):
    """ Parse needed fields from raw json and return dict representing
            a unit
        """
    unit = {}
    fields = {'serial', 'label', 'address', 'password', 'cryptoSerial'}
    try:
        for field in fields:
            unit[field] = raw_unit[field]
    except KeyError:
        pass
    return unit
