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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 upsert(self, key, value, cas=0, ttl=0, format=None, persist_to=0, replicate_to=0):
 """Unconditionally store the object in Couchbase. :param key: The key to set the value with. By default, the key must be either a :class:`bytes` or :class:`str` object encodable as UTF-8. If a custom `transcoder` class is used (see :meth:`~__init__`), then the key object is passed directly to the transcoder, which may serialize it how it wishes. :type key: string or bytes :param value: The value to set for the key. This should be a native Python value which will be transparently serialized to JSON by the library. Do not pass already-serialized JSON as the value or it will be serialized again. If you are using a different `format` setting (see `format` parameter), and/or a custom transcoder then value for this argument may need to conform to different criteria. :param int cas: The _CAS_ value to use. If supplied, the value will only be stored if it already exists with the supplied CAS :param int ttl: If specified, the key will expire after this many seconds :param int format: If specified, indicates the `format` to use when encoding the value. If none is specified, it will use the `default_format` For more info see :attr:`~.default_format` :param int persist_to: Perform durability checking on this many nodes nodes for persistence to disk. See :meth:`endure` for more information :param int replicate_to: Perform durability checking on this many replicas for presence in memory. See :meth:`endure` for more information. :raise: :exc:`.ArgumentError` if an argument is supplied that is not applicable in this context. For example setting the CAS as a string. :raise: :exc`.CouchbaseNetworkError` :raise: :exc:`.KeyExistsError` if the key already exists on the server with a different CAS value. :raise: :exc:`.ValueFormatError` if the value cannot be serialized with chosen encoder, e.g. if you try to store a dictionary in plain mode. :return: :class:`~.Result`. Simple set:: cb.upsert('key', 'value') Force JSON document format for value:: cb.upsert('foo', {'bar': 'baz'}, format=couchbase.FMT_JSON) Insert JSON from a string:: JSONstr = '{"key1": "value1", "key2": 123}' JSONobj = json.loads(JSONstr) cb.upsert("documentID", JSONobj, format=couchbase.FMT_JSON) Force UTF8 document format for value:: cb.upsert('foo', "<xml></xml>", format=couchbase.FMT_UTF8) Perform optimistic locking by specifying last known CAS version:: cb.upsert('foo', 'bar', cas=8835713818674332672) Several sets at the same time (mutli-set):
: cb.upsert_multi({'foo': 'bar', 'baz': 'value'}) .. seealso:: :meth:`upsert_multi` """

        return _Base.upsert(self, key, value, cas=cas, ttl=ttl,
                            format=format, persist_to=persist_to,
                            replicate_to=replicate_to)