How to use the acme.jose.errors.DeserializationError function in acme

    @crit.decoder
    def crit(unused_value):
        # pylint: disable=missing-docstring,no-self-argument,no-self-use
        raise errors.DeserializationError(
            '"crit" is not supported, please subclass')

def decode_b64jose(data, size=None, minimum=False):
    """Decode JOSE Base-64 field.

    :param unicode data:
    :param int size: Required length (after decoding).
    :param bool minimum: If ``True``, then `size` will be treated as
        minimum required length, as opposed to exact equality.

    :rtype: bytes

    """
    error_cls = TypeError if six.PY2 else binascii.Error
    try:
        decoded = b64.b64decode(data.encode())
    except error_cls as error:
        raise errors.DeserializationError(error)

    if size is not None and ((not minimum and len(decoded) != size) or
                             (minimum and len(decoded) < size)):
        raise errors.DeserializationError(
            "Expected at least or exactly {0} bytes".format(size))

    return decoded

:param int size: Required length (after decoding).
    :param bool minimum: If ``True``, then `size` will be treated as
        minimum required length, as opposed to exact equality.

    :rtype: bytes

    """
    error_cls = TypeError if six.PY2 else binascii.Error
    try:
        decoded = b64.b64decode(data.encode())
    except error_cls as error:
        raise errors.DeserializationError(error)

    if size is not None and ((not minimum and len(decoded) != size) or
                             (minimum and len(decoded) < size)):
        raise errors.DeserializationError(
            "Expected at least or exactly {0} bytes".format(size))

    return decoded

if cls in six.itervalues(cls.TYPES):
            if cls.type_field_name not in jobj:
                raise errors.DeserializationError(
                    "Missing type field ({0})".format(cls.type_field_name))
            # cls is already registered type_cls, force to use it
            # so that, e.g Revocation.from_json(jobj) fails if
            # jobj["type"] != "revocation".
            return cls

        if not isinstance(jobj, dict):
            raise errors.DeserializationError(
                "{0} is not a dictionary object".format(jobj))
        try:
            typ = jobj[cls.type_field_name]
        except KeyError:
            raise errors.DeserializationError("missing type field")

        try:
            return cls.TYPES[typ]
        except KeyError:
            raise errors.UnrecognizedTypeError(typ, jobj)

def decode_b64jose(data, size=None, minimum=False):
    """Decode JOSE Base-64 field.

    :param unicode data:
    :param int size: Required length (after decoding).
    :param bool minimum: If ``True``, then `size` will be treated as
        minimum required length, as opposed to exact equality.

    :rtype: bytes

    """
    error_cls = TypeError if six.PY2 else binascii.Error
    try:
        decoded = b64.b64decode(data.encode())
    except error_cls as error:
        raise errors.DeserializationError(error)

    if size is not None and ((not minimum and len(decoded) != size) or
                             (minimum and len(decoded) < size)):
        raise errors.DeserializationError(
            "Expected at least or exactly {0} bytes".format(size))

    return decoded

def decode_csr(b64der):
    """Decode JOSE Base-64 DER-encoded CSR.

    :param unicode b64der:
    :rtype: `OpenSSL.crypto.X509Req` wrapped in `.ComparableX509`

    """
    try:
        return util.ComparableX509(OpenSSL.crypto.load_certificate_request(
            OpenSSL.crypto.FILETYPE_ASN1, decode_b64jose(b64der)))
    except OpenSSL.crypto.Error as error:
        raise errors.DeserializationError(error)

    @classmethod
    def fields_from_json(cls, jobj):
        fields = super(Signature, cls).fields_from_json(jobj)
        fields_with_combined = cls._with_combined(fields)
        if 'alg' not in fields_with_combined['combined'].not_omitted():
            raise errors.DeserializationError('alg not present')
        return fields_with_combined