def dump_flows_for(self, **kwargs):
        retval = None
        if "cookie" in kwargs:
            kwargs["cookie"] = check_cookie_mask(str(kwargs["cookie"]))
        flow_str = ",".join("=".join([key, str(val)])
            for key, val in kwargs.items())

        flows = self.run_ofctl("dump-flows", [flow_str])
        if flows:
            retval = '\n'.join(item for item in flows.splitlines()
                               if item not in 'NXST')
        return retval
dataset/ETHPy150Open openstack/neutron/neutron/agent/common/ovs_lib.py/OVSBridge.dump_flows_for/swapped operands of `not in`