How to use the josepy.Field function in josepy

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

    :ivar josepy.jwk.JWK key: Public key.
    :ivar tuple contact: Contact information following ACME spec,
        `tuple` of `unicode`.
    :ivar unicode agreement:

    """
    # on new-reg key server ignores 'key' and populates it based on
    # JWS.signature.combined.jwk
    key = jose.Field('key', omitempty=True, decoder=jose.JWK.from_json)
    contact = jose.Field('contact', omitempty=True, default=())
    agreement = jose.Field('agreement', omitempty=True)
    status = jose.Field('status', omitempty=True)
    terms_of_service_agreed = jose.Field('termsOfServiceAgreed', omitempty=True)
    only_return_existing = jose.Field('onlyReturnExisting', omitempty=True)
    external_account_binding = jose.Field('externalAccountBinding', omitempty=True)

    phone_prefix = 'tel:'
    email_prefix = 'mailto:'

    @classmethod
    def from_data(cls, phone=None, email=None, external_account_binding=None, **kwargs):
        """Create registration resource from contact details."""
        details = list(kwargs.pop('contact', ()))
        if phone is not None:
            details.append(cls.phone_prefix + phone)
        if email is not None:
            details.extend([cls.email_prefix + mail for mail in email.split(',')])
        kwargs['contact'] = tuple(details)

return tuple(Identifier.from_json(identifier) for identifier in value)

class OrderResource(ResourceWithURI):
    """Order Resource.

    :ivar acme.messages.Order body:
    :ivar str csr_pem: The CSR this Order will be finalized with.
    :ivar list of acme.messages.AuthorizationResource authorizations:
        Fully-fetched AuthorizationResource objects.
    :ivar str fullchain_pem: The fetched contents of the certificate URL
        produced once the order was finalized, if it's present.
    """
    body = jose.Field('body', decoder=Order.from_json)
    csr_pem = jose.Field('csr_pem', omitempty=True)
    authorizations = jose.Field('authorizations')
    fullchain_pem = jose.Field('fullchain_pem', omitempty=True)

@Directory.register
class NewOrder(Order):
    """New order."""
    resource_type = 'new-order'

class IdentifierType(_Constant):
    """ACME identifier type."""
    POSSIBLE_NAMES = {}  # type: dict
IDENTIFIER_FQDN = IdentifierType('dns')  # IdentifierDNS in Boulder


class Identifier(jose.JSONObjectWithFields):
    """ACME identifier.

    :ivar IdentifierType typ:
    :ivar unicode value:

    """
    typ = jose.Field('type', decoder=IdentifierType.from_json)
    value = jose.Field('value')


class Directory(jose.JSONDeSerializable):
    """Directory."""

    _REGISTERED_TYPES = {}  # type: dict

    class Meta(jose.JSONObjectWithFields):
        """Directory Meta."""
        _terms_of_service = jose.Field('terms-of-service', omitempty=True)
        _terms_of_service_v2 = jose.Field('termsOfService', omitempty=True)
        website = jose.Field('website', omitempty=True)
        caa_identities = jose.Field('caaIdentities', omitempty=True)
        external_account_required = jose.Field('externalAccountRequired', omitempty=True)

def nonce(value):  # pylint: disable=missing-docstring,no-self-argument
        try:
            return jose.decode_b64jose(value)
        except jose.DeserializationError as error:
            # TODO: custom error
            raise jose.DeserializationError("Invalid nonce: {0}".format(error))


class Signature(jose.Signature):
    """ACME-specific Signature. Uses ACME-specific Header for customer fields."""
    __slots__ = jose.Signature._orig_slots  # pylint: disable=no-member

    # TODO: decoder/encoder should accept cls? Otherwise, subclassing
    # JSONObjectWithFields is tricky...
    header_cls = Header
    header = jose.Field(
        'header', omitempty=True, default=header_cls(),
        decoder=header_cls.from_json)

    # TODO: decoder should check that nonce is in the protected header


class JWS(jose.JWS):
    """ACME-specific JWS. Includes none, url, and kid in protected header."""
    signature_cls = Signature
    __slots__ = jose.JWS._orig_slots  # pylint: disable=no-member

    @classmethod
    # pylint: disable=arguments-differ
    def sign(cls, payload, key, alg, nonce, url=None, kid=None):
        # Per ACME spec, jwk and kid are mutually exclusive, so only include a
        # jwk field if kid is not provided.

return (ERROR_PREFIX in err.typ) or (OLD_ERROR_PREFIX in err.typ)
    return False


@six.python_2_unicode_compatible
class Error(jose.JSONObjectWithFields, errors.Error):
    """ACME error.

    https://tools.ietf.org/html/draft-ietf-appsawg-http-problem-00

    :ivar unicode typ:
    :ivar unicode title:
    :ivar unicode detail:

    """
    typ = jose.Field('type', omitempty=True, default='about:blank')
    title = jose.Field('title', omitempty=True)
    detail = jose.Field('detail', omitempty=True)

    @classmethod
    def with_code(cls, code, **kwargs):
        """Create an Error instance with an ACME Error code.

        :unicode code: An ACME error code, like 'dnssec'.
        :kwargs: kwargs to pass to Error.

        """
        if code not in ERROR_CODES:
            raise ValueError("The supplied code: %s is not a known ACME error"
                             " code" % code)
        typ = ERROR_PREFIX + code
        return cls(typ=typ, **kwargs)

"""Order Resource Body.

    :ivar list of .Identifier: List of identifiers for the certificate.
    :ivar acme.messages.Status status:
    :ivar list of str authorizations: URLs of authorizations.
    :ivar str certificate: URL to download certificate as a fullchain PEM.
    :ivar str finalize: URL to POST to to request issuance once all
        authorizations have "valid" status.
    :ivar datetime.datetime expires: When the order expires.
    :ivar .Error error: Any error that occurred during finalization, if applicable.
    """
    identifiers = jose.Field('identifiers', omitempty=True)
    status = jose.Field('status', decoder=Status.from_json,
                        omitempty=True)
    authorizations = jose.Field('authorizations', omitempty=True)
    certificate = jose.Field('certificate', omitempty=True)
    finalize = jose.Field('finalize', omitempty=True)
    expires = fields.RFC3339Field('expires', omitempty=True)
    error = jose.Field('error', omitempty=True, decoder=Error.from_json)

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

class OrderResource(ResourceWithURI):
    """Order Resource.

    :ivar acme.messages.Order body:
    :ivar str csr_pem: The CSR this Order will be finalized with.
    :ivar list of acme.messages.AuthorizationResource authorizations:
        Fully-fetched AuthorizationResource objects.
    :ivar str fullchain_pem: The fetched contents of the certificate URL

def load(self, account_id):
        try:
            return self.accounts[account_id]
        except KeyError:
            raise errors.AccountNotFound(account_id)

class RegistrationResourceWithNewAuthzrURI(messages.RegistrationResource):
    """A backwards-compatible RegistrationResource with a new-authz URI.

       Hack: Certbot versions pre-0.11.1 expect to load
       new_authzr_uri as part of the account. Because people
       sometimes switch between old and new versions, we will
       continue to write out this field for some time so older
       clients don't crash in that scenario.
    """
    new_authzr_uri = jose.Field('new_authzr_uri')

class AccountFileStorage(interfaces.AccountStorage):
    """Accounts file storage.

    :ivar .IConfig config: Client configuration

    """
    def __init__(self, config):
        self.config = config
        util.make_or_verify_dir(config.accounts_dir, 0o700, self.config.strict_permissions)

    def _account_dir_path(self, account_id):
        return self._account_dir_path_for_server_path(account_id, self.config.server_path)

    def _account_dir_path_for_server_path(self, account_id, server_path):
        accounts_dir = self.config.accounts_dir_for_server_path(server_path)

:ivar IdentifierType typ:
    :ivar unicode value:

    """
    typ = jose.Field('type', decoder=IdentifierType.from_json)
    value = jose.Field('value')


class Directory(jose.JSONDeSerializable):
    """Directory."""

    _REGISTERED_TYPES = {}  # type: dict

    class Meta(jose.JSONObjectWithFields):
        """Directory Meta."""
        _terms_of_service = jose.Field('terms-of-service', omitempty=True)
        _terms_of_service_v2 = jose.Field('termsOfService', omitempty=True)
        website = jose.Field('website', omitempty=True)
        caa_identities = jose.Field('caaIdentities', omitempty=True)
        external_account_required = jose.Field('externalAccountRequired', omitempty=True)

        def __init__(self, **kwargs):
            kwargs = dict((self._internal_name(k), v) for k, v in kwargs.items())
            super(Directory.Meta, self).__init__(**kwargs)

        @property
        def terms_of_service(self):
            """URL for the CA TOS"""
            return self._terms_of_service or self._terms_of_service_v2

        def __iter__(self):
            # When iterating over fields, use the external name 'terms_of_service' instead of

"""Update registration."""
    resource_type = 'reg'
    resource = fields.Resource(resource_type)


class RegistrationResource(ResourceWithURI):
    """Registration Resource.

    :ivar acme.messages.Registration body:
    :ivar unicode new_authzr_uri: Deprecated. Do not use.
    :ivar unicode terms_of_service: URL for the CA TOS.

    """
    body = jose.Field('body', decoder=Registration.from_json)
    new_authzr_uri = jose.Field('new_authzr_uri', omitempty=True)
    terms_of_service = jose.Field('terms_of_service', omitempty=True)


class ChallengeBody(ResourceBody):
    """Challenge Resource Body.

    .. todo::
       Confusingly, this has a similar name to `.challenges.Challenge`,
       as well as `.achallenges.AnnotatedChallenge`. Please use names
       such as ``challb`` to distinguish instances of this class from
       ``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:

"""ACME-specific JWS.

The JWS implementation in josepy only implements the base JOSE standard. In
order to support the new header fields defined in ACME, this module defines some
ACME-specific classes that layer on top of josepy.
"""
import josepy as jose


class Header(jose.Header):
    """ACME-specific JOSE Header. Implements nonce, kid, and url.
    """
    nonce = jose.Field('nonce', omitempty=True, encoder=jose.encode_b64jose)
    kid = jose.Field('kid', omitempty=True)
    url = jose.Field('url', omitempty=True)

    @nonce.decoder
    def nonce(value):  # pylint: disable=missing-docstring,no-self-argument
        try:
            return jose.decode_b64jose(value)
        except jose.DeserializationError as error:
            # TODO: custom error
            raise jose.DeserializationError("Invalid nonce: {0}".format(error))


class Signature(jose.Signature):
    """ACME-specific Signature. Uses ACME-specific Header for customer fields."""
    __slots__ = jose.Signature._orig_slots  # pylint: disable=no-member