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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 assertion_jwt(client_id, keys, audience, algorithm, lifetime=600):
 """ Create a signed Json Web Token containing some information. :param client_id: The Client ID :param keys: Signing keys :param audience: Who is the receivers for this assertion :param algorithm: Signing algorithm :param lifetime: The lifetime of the signed Json Web Token :return: A Signed Json Web Token """

    _now = utc_time_sans_frac()

    at = AuthnToken(iss=client_id, sub=client_id,
                    aud=audience, jti=rndstr(32),
                    exp=_now + lifetime, iat=_now)
    logger.debug('AuthnToken: {}'.format(at.to_dict()))
    return at.to_jwt(key=keys, algorithm=algorithm)