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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 _construct_single(self, basedir, port, name=None, extra=''):
 """ Construct command line strings for a single node. Handles shards and stand-alones. """

        datapath = self._create_paths(basedir, name)
        self._construct_mongod(os.path.join(datapath, 'db'),
                               os.path.join(datapath, 'mongod.log'), port,
                               replset=None, extra=extra)

        host = '%s:%i' % (self.args['hostname'], port)

        return host