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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 publish(self, topic=None, msg=None, modname=None, pre_fire_hook=None, **kw):
 """ Send a message over the publishing zeromq socket. The above snippet will send the message ``'{test: "Hello World"}'`` over the ``<topic_prefix>.dev.test.testing`` topic. The fully qualified topic of a message is constructed out of the following pieces: <:ref:`conf-topic-prefix`>.<:ref:`conf-environment`>.<``modname``>.<``topic``> This function (and other API functions) do a little bit more heavy lifting than they let on. If the "zeromq context" is not yet initialized, :func:`fedmsg.init` is called to construct it and store it as :data:`fedmsg.__local.__context` before anything else is done. **An example from Fedora Tagger -- SQLAlchemy encoding** Here's an example from `fedora-tagger <https://github.com/fedora-infra/fedora-tagger>`_ that sends the information about a new tag over ``org.fedoraproject.{dev,stg,prod}.fedoratagger.tag.update``:: Note that the `tag` and `user` objects are SQLAlchemy objects defined by tagger. They both have ``.__json__()`` methods which :func:`fedmsg.publish` uses to encode both objects as stringified JSON for you. Under the hood, specifically, ``.publish`` uses :mod:`fedmsg.encoding` to do this. ``fedmsg`` has also guessed the module name (``modname``) of it's caller and inserted it into the topic for you. The code from which we stole the above snippet lives in ``fedoratagger.controllers.root``. ``fedmsg`` figured that out and stripped it down to just ``fedoratagger`` for the final topic of ``org.fedoraproject.{dev,stg,prod}.fedoratagger.tag.update``. **Shell Usage** You could also use the ``fedmsg-logger`` from a shell script like so:: $ echo "Hello, world." | fedmsg-logger --topic testing $ echo '{"foo": "bar"}' | fedmsg-logger --json-input :param topic: The message topic suffix. This suffix is joined to the configured topic prefix (e.g. ``org.fedoraproject``), environment (e.g. ``prod``, ``dev``, etc.), and modname. :type topic: unicode :param msg: A message to publish. This message will be JSON-encoded prior to being sent, so the object must be composed of JSON- serializable data types. Please note that if this is already a string JSON serialization will be applied to that string. :type msg: dict :param modname: The module name that is publishing the message. If this is omitted, ``fedmsg`` will try to guess the name of the module that called it and use that to produce an intelligent topic. Specifying ``modname`` explicitly overrides this behavior. :type modname: unicode :param pre_fire_hook: A callable that will be called with a single argument -- the dict of the constructed message -- just before it is handed off to ZeroMQ for publication. :type pre_fire_hook: function """


        topic = topic or 'unspecified'
        msg = msg or dict()

        # If no modname is supplied, then guess it from the call stack.
        modname = modname or guess_calling_module(default="fedmsg")
        topic = '.'.join([modname, topic])

        if topic[:len(self.c['topic_prefix'])] != self.c['topic_prefix']:
            topic = '.'.join([
                self.c['topic_prefix'],
                self.c['environment'],
                topic,
            ])

        if isinstance(topic, six.text_type):
            topic = to_bytes(topic, encoding='utf8', nonstring="passthru")

        year = datetime.datetime.now().year

        self._i += 1
        msg = dict(
            topic=topic.decode('utf-8'),
            msg=msg,
            timestamp=int(time.time()),
            msg_id=str(year) + '-' + str(uuid.uuid4()),
            i=self._i,
            username=getpass.getuser(),
        )

        # Find my message-signing cert if I need one.
        if self.c.get('sign_messages', False):
            if not self.c.get("crypto_backend") == "gpg":
                if 'cert_prefix' in self.c:
                    cert_index = "%s.%s" % (self.c['cert_prefix'],
                                            self.hostname)
                else:
                    cert_index = self.c['name']
                    if cert_index == 'relay_inbound':
                        cert_index = "shell.%s" % self.hostname

                self.c['certname'] = self.c['certnames'][cert_index]
            else:
                if 'gpg_signing_key' not in self.c:
                    self.c['gpg_signing_key'] = self.c['gpg_keys'][self.hostname]

        if self.c.get('sign_messages', False):
            msg = fedmsg.crypto.sign(msg, **self.c)

        store = self.c.get('persistent_store', None)
        if store:
            # Add the seq_id field
            msg = store.add(msg)

        if pre_fire_hook:
            pre_fire_hook(msg)

        # We handle zeromq publishing ourselves.  But, if that is disabled,
        # defer to the moksha' hub's twisted reactor to send messages (if
        # available).
        if self.c.get('zmq_enabled', True):
            self.publisher.send_multipart(
                [topic, fedmsg.encoding.dumps(msg).encode('utf-8')],
                flags=zmq.NOBLOCK,
            )
        else:
            # Perhaps we're using STOMP or AMQP?  Let moksha handle it.
            import moksha.hub
            # First, a quick sanity check.
            if not getattr(moksha.hub, '_hub', None):
                raise AttributeError("Unable to publish non-zeromq msg "
                                     "without moksha-hub initialization.")
            # Let moksha.hub do our work.
            moksha.hub._hub.send_message(
                topic=topic,
                message=fedmsg.encoding.dumps(msg).encode('utf-8'),
                jsonify=False,
            )