new_contents: from config.experiment_config_lib import ControllerConfig
  from sts.topology import StarTopology, BufferedPatchPanel, MeshTopology, GridTopology, BinaryLeafTreeTopology
  from sts.controller_manager import UserSpaceControllerPatchPanel
  from sts.control_flow.fuzzer import Fuzzer
  from sts.control_flow.interactive import Interactive
  from sts.input_traces.input_logger import InputLogger
  from sts.simulation_state import SimulationConfig
  from sts.happensbefore.hb_logger import HappensBeforeLogger
  from config.application_events import AppCircuitPusher
  
  
  
  # Use POX as our controller
  start_cmd = ('''./pox.py --verbose '''
                '''openflow.discovery forwarding.l2_multi '''
               '''openflow.of_01 --address=__address__ --port=__port__ ''')
  
  controllers = [ControllerConfig(start_cmd, cwd="pox/")]
  
  topology_class = StarTopology
  topology_params = "num_hosts=3"
  # topology_class = MeshTopology
  # topology_params = "num_switches=5"
  
  # Where should the output files be written to
  results_dir = "traces/pox_l2_multi-star3-traffic-failures"
  
  apps = None
  
  # include all defaults
  simulation_config = SimulationConfig(controller_configs=controllers,
                                       topology_class=topology_class,
                                       topology_params=topology_params,
                                       patch_panel_class=BufferedPatchPanel,
                                       controller_patch_panel_class=UserSpaceControllerPatchPanel,
                                       dataplane_trace=None,
                                       snapshot_service=None,
                                       multiplex_sockets=False,
                                       violation_persistence_threshold=None,
                                       kill_controllers_on_exit=True,
                                       interpose_on_controllers=False,
                                       ignore_interposition=False,
                                       hb_logger_class=HappensBeforeLogger,
                                       hb_logger_params=results_dir,
                                       apps=apps)
  
  # Manual, interactive mode
  # control_flow = Interactive(simulation_config, input_logger=InputLogger())
  
  control_flow = Fuzzer(simulation_config,
                        input_logger=InputLogger(),
                        initialization_rounds=20,
                        send_all_to_all=False,
                        check_interval=1,
                        delay=0.1,
                        halt_on_violation=True,
  #                       invariant_check_name="check_everything",
                        invariant_check_name="InvariantChecker.check_liveness",
                        apps=apps)
subject: Add config for POX l2_multi traces