How to use the acme.jose.Field function in acme

:ivar JWK jwk: JSON Web Key
        :ivar tuple cert_fingerprints: `tuple` of `unicode`
        :ivar tuple certs: Sequence of :class:`acme.jose.ComparableX509`
            certificates.
        :ivar tuple subject_key_identifiers: `tuple` of `unicode`
        :ivar tuple issuers: `tuple` of `unicode`
        :ivar tuple authorized_for: `tuple` of `unicode`

        """
        jwk = jose.Field("jwk", decoder=jose.JWK.from_json)
        cert_fingerprints = jose.Field(
            "certFingerprints", omitempty=True, default=())
        certs = jose.Field("certs", omitempty=True, default=())
        subject_key_identifiers = jose.Field(
            "subjectKeyIdentifiers", omitempty=True, default=())
        serial_numbers = jose.Field("serialNumbers", omitempty=True, default=())
        issuers = jose.Field("issuers", omitempty=True, default=())
        authorized_for = jose.Field("authorizedFor", omitempty=True, default=())

        @certs.encoder
        def certs(value):  # pylint: disable=missing-docstring,no-self-argument
            return tuple(jose.encode_cert(cert) for cert in value)

        @certs.decoder
        def certs(value):  # pylint: disable=missing-docstring,no-self-argument
            return tuple(jose.decode_cert(cert) for cert in value)

    alg = jose.Field("alg", decoder=jose.JWASignature.from_json)
    nonce = jose.Field(
        "nonce", encoder=jose.encode_b64jose, decoder=functools.partial(
            jose.decode_b64jose, size=NONCE_SIZE))
    hints = jose.Field("hints", decoder=Hints.from_json)

hints = jose.Field("hints", decoder=Hints.from_json)


@ChallengeResponse.register
class ProofOfPossessionResponse(ChallengeResponse):
    """ACME "proofOfPossession" challenge response.

    :ivar bytes nonce: Random data, **not** base64-encoded.
    :ivar acme.other.Signature signature: Sugnature of this message.

    """
    typ = "proofOfPossession"

    NONCE_SIZE = ProofOfPossession.NONCE_SIZE

    nonce = jose.Field(
        "nonce", encoder=jose.encode_b64jose, decoder=functools.partial(
            jose.decode_b64jose, size=NONCE_SIZE))
    signature = jose.Field("signature", decoder=other.Signature.from_json)

    def verify(self):
        """Verify the challenge."""
        # self.signature is not Field | pylint: disable=no-member
        return self.signature.verify(self.nonce)


@Challenge.register  # pylint: disable=too-many-ancestors
class DNS(_TokenDVChallenge):
    """ACME "dns" challenge."""
    typ = "dns"

    LABEL = "_acme-challenge"

    @classmethod
    def from_json(cls, jobj):
        return cls(jobj)


class _TokenDVChallenge(DVChallenge):
    """DV Challenge with token.

    :ivar bytes token:

    """
    TOKEN_SIZE = 128 / 8  # Based on the entropy value from the spec
    """Minimum size of the :attr:`token` in bytes."""

    # TODO: acme-spec doesn't specify token as base64-encoded value
    token = jose.Field(
        "token", encoder=jose.encode_b64jose, decoder=functools.partial(
            jose.decode_b64jose, size=TOKEN_SIZE, minimum=True))

    # XXX: rename to ~token_good_for_url
    @property
    def good_token(self):  # XXX: @token.decoder
        """Is `token` good?

        .. todo:: acme-spec wants "It MUST NOT contain any non-ASCII
           characters", but it should also warrant that it doesn't
           contain ".." or "/"...

        """
        # TODO: check that path combined with uri does not go above
        # URI_ROOT_PATH!
        return b'..' not in self.token and b'/' not in self.token

@Directory.register
class NewAuthorization(Authorization):
    """New authorization."""
    resource_type = 'new-authz'
    resource = fields.Resource(resource_type)


class AuthorizationResource(ResourceWithURI):
    """Authorization Resource.

    :ivar acme.messages.Authorization body:
    :ivar unicode new_cert_uri: URI found in the 'next' ``Link`` header

    """
    body = jose.Field('body', decoder=Authorization.from_json)
    new_cert_uri = jose.Field('new_cert_uri')


@Directory.register
class CertificateRequest(jose.JSONObjectWithFields):
    """ACME new-cert request.

    :ivar acme.jose.util.ComparableX509 csr:
        `OpenSSL.crypto.X509Req` wrapped in `.ComparableX509`

    """
    resource_type = 'new-cert'
    resource = fields.Resource(resource_type)
    csr = jose.Field('csr', decoder=jose.decode_csr, encoder=jose.encode_csr)


class CertificateResource(ResourceWithURI):

return self.response(account_key).gen_cert(key=kwargs.get('cert_key'))


@Challenge.register
class RecoveryContact(ContinuityChallenge):
    """ACME "recoveryContact" challenge.

    :ivar unicode activation_url:
    :ivar unicode success_url:
    :ivar unicode contact:

    """
    typ = "recoveryContact"

    activation_url = jose.Field("activationURL", omitempty=True)
    success_url = jose.Field("successURL", omitempty=True)
    contact = jose.Field("contact", omitempty=True)


@ChallengeResponse.register
class RecoveryContactResponse(ChallengeResponse):
    """ACME "recoveryContact" challenge response.

    :ivar unicode token:

    """
    typ = "recoveryContact"
    token = jose.Field("token", omitempty=True)


@Challenge.register
class ProofOfPossession(ContinuityChallenge):

@Directory.register
class NewAuthorization(Authorization):
    """New authorization."""
    resource_type = 'new-authz'
    resource = fields.Resource(resource_type)


class AuthorizationResource(ResourceWithURI):
    """Authorization Resource.

    :ivar acme.messages.Authorization body:
    :ivar unicode new_cert_uri: URI found in the 'next' ``Link`` header

    """
    body = jose.Field('body', decoder=Authorization.from_json)
    new_cert_uri = jose.Field('new_cert_uri')


@Directory.register
class CertificateRequest(jose.JSONObjectWithFields):
    """ACME new-cert request.

    :ivar acme.jose.util.ComparableX509 csr:
        `OpenSSL.crypto.X509Req` wrapped in `.ComparableX509`

    """
    resource_type = 'new-cert'
    resource = fields.Resource(resource_type)
    csr = jose.Field('csr', decoder=jose.decode_csr, encoder=jose.encode_csr)

# pylint: disable=function-redefined
        return self.body.uri  # pylint: disable=no-member


class Authorization(ResourceBody):
    """Authorization Resource Body.

    :ivar acme.messages.Identifier identifier:
    :ivar list challenges: `list` of `.ChallengeBody`
    :ivar tuple combinations: Challenge combinations (`tuple` of `tuple`
        of `int`, as opposed to `list` of `list` from the spec).
    :ivar acme.messages.Status status:
    :ivar datetime.datetime expires:

    """
    identifier = jose.Field('identifier', decoder=Identifier.from_json)
    challenges = jose.Field('challenges', omitempty=True)
    combinations = jose.Field('combinations', omitempty=True)

    status = jose.Field('status', omitempty=True, decoder=Status.from_json)
    # TODO: 'expires' is allowed for Authorization Resources in
    # general, but for Key Authorization '[t]he "expires" field MUST
    # be absent'... then acme-spec gives example with 'expires'
    # present... That's confusing!
    expires = fields.RFC3339Field('expires', omitempty=True)

    @challenges.decoder
    def challenges(value):  # pylint: disable=missing-docstring,no-self-argument
        return tuple(ChallengeBody.from_json(chall) for chall in value)

    @property
    def resolved_combinations(self):

class Signature(jose.JSONObjectWithFields):
    """ACME signature.

    :ivar .JWASignature alg: Signature algorithm.
    :ivar bytes sig: Signature.
    :ivar bytes nonce: Nonce.
    :ivar .JWK jwk: JWK.

    """
    NONCE_SIZE = 16
    """Minimum size of nonce in bytes."""

    alg = jose.Field('alg', decoder=jose.JWASignature.from_json)
    sig = jose.Field('sig', encoder=jose.encode_b64jose,
                     decoder=jose.decode_b64jose)
    nonce = jose.Field(
        'nonce', encoder=jose.encode_b64jose, decoder=functools.partial(
            jose.decode_b64jose, size=NONCE_SIZE, minimum=True))
    jwk = jose.Field('jwk', decoder=jose.JWK.from_json)

    @classmethod
    def from_msg(cls, msg, key, nonce=None, nonce_size=None, alg=jose.RS256):
        """Create signature with nonce prepended to the message.

        :param bytes msg: Message to be signed.

        :param key: Key used for signing.
        :type key: `cryptography.hazmat.primitives.asymmetric.rsa.RSAPrivateKey`
            (optionally wrapped in `.ComparableRSAKey`).

``achall``.

    :ivar acme.challenges.Challenge: Wrapped challenge.
        Conveniently, all challenge fields are proxied, i.e. you can
        call ``challb.x`` to get ``challb.chall.x`` contents.
    :ivar acme.messages.Status status:
    :ivar datetime.datetime validated:
    :ivar messages.Error error:

    """
    __slots__ = ('chall',)
    uri = jose.Field('uri')
    status = jose.Field('status', decoder=Status.from_json,
                        omitempty=True, default=STATUS_PENDING)
    validated = fields.RFC3339Field('validated', omitempty=True)
    error = jose.Field('error', decoder=Error.from_json,
                       omitempty=True, default=None)

    def to_partial_json(self):
        jobj = super(ChallengeBody, self).to_partial_json()
        jobj.update(self.chall.to_partial_json())
        return jobj

    @classmethod
    def fields_from_json(cls, jobj):
        jobj_fields = super(ChallengeBody, cls).fields_from_json(jobj)
        jobj_fields['chall'] = challenges.Challenge.from_json(jobj)
        return jobj_fields

    def __getattr__(self, name):
        return getattr(self.chall, name)