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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, version_id=None):
 """ Creates a publish task just for this version, which publishes as soon as any import is complete. :return: the publish task :rtype: Publish :raises Conflict: If the version is already published, or already has a publish job. """

        if not version_id:
            version_id = self.version.id

        target_url = self._client.get_url('VERSION', 'POST', 'publish', {'layer_id': self.id, 'version_id': version_id})
        r = self._client.request('POST', target_url, json={})
        return self._client.get_manager(Publish).create_from_result(r.json())