@staticmethod
def _passwords_generator(streams, pwlen):
    """ Generator that dumps the passwords for each card read strategy """
    for stream in streams['default']:
        counter = 0
        while counter + pwlen < len(stream) + 1:
            result = stream[counter:counter + pwlen]
            yield ''.join(result)
            counter += 1
    if streams.get('spiral'):
        for stream in streams['spiral']:
            if len(stream) >= pwlen:
                result = stream[0:pwlen]
                yield ''.join(result)
