Creates a new hunt.

def _HandleLegacy(self, args, token=None):
    """Creates a new hunt."""

    # We only create generic hunts with /hunts/create requests.
    generic_hunt_args = rdf_hunts.GenericHuntArgs()
    generic_hunt_args.flow_runner_args.flow_name = args.flow_name
    generic_hunt_args.flow_args = args.flow_args

    # Clear all fields marked with HIDDEN, except for output_plugins - they are
    # marked HIDDEN, because we have a separate UI for them, not because they
    # shouldn't be shown to the user at all.
    #
    # TODO(user): Refactor the code to remove the HIDDEN label from
    # HuntRunnerArgs.output_plugins.
    args.hunt_runner_args.ClearFieldsWithLabel(
        rdf_structs.SemanticDescriptor.Labels.HIDDEN,
        exceptions="output_plugins")
    args.hunt_runner_args.hunt_name = standard.GenericHunt.__name__

    if args.original_hunt and args.original_flow:
      raise ValueError(
          "A hunt can't be a copy of a flow and a hunt at the same time.")
    if args.original_hunt:
      ref = rdf_hunts.FlowLikeObjectReference.FromHuntId(
          utils.SmartStr(args.original_hunt.hunt_id))
      args.hunt_runner_args.original_object = ref
    elif args.original_flow:
      ref = rdf_hunts.FlowLikeObjectReference.FromFlowIdAndClientId(
          utils.SmartStr(args.original_flow.flow_id),
          utils.SmartStr(args.original_flow.client_id))
      args.hunt_runner_args.original_object = ref

    # Anyone can create the hunt but it will be created in the paused
    # state. Permissions are required to actually start it.
    with implementation.StartHunt(
        runner_args=args.hunt_runner_args, args=generic_hunt_args,
        token=token) as hunt_obj:

      # Nothing really to do here - hunts are always created in the paused
      # state.
      logging.info("User %s created a new %s hunt (%s)", token.username,
                   hunt_obj.args.flow_runner_args.flow_name, hunt_obj.urn)

      return ApiHunt().InitFromAff4Object(hunt_obj, with_full_summary=True)