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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 get_ofport(self, port_name):
 """ Gets the OpenFlow port number. This method is corresponding to the following ovs-vsctl command:: $ ovs-vsctl get Interface <port> ofport """

        ofport_list = self.db_get_val('Interface', port_name, 'ofport')
        assert len(ofport_list) == 1
        return int(ofport_list[0])