def handle(slice):
    from core.models import Controller, ControllerSlice, SiteDeployment, Network, NetworkSlice,NetworkTemplate, Slice
    from collections import defaultdict

    # slice = Slice.get(slice_id)

    controller_slices = ControllerSlice.objects.filter(slice=slice)
    existing_controllers = [cs.controller for cs in controller_slices] 
        
    all_controllers = Controller.objects.all() 
    for controller in all_controllers:
        if controller not in existing_controllers:
            sd = ControllerSlice(slice=slice, controller=controller)
            sd.save()

    # make sure slice has at least 1 public and 1 private networkd
    public_nets = []
    private_net = None
    networks = Network.objects.filter(owner=slice)
    for network in networks:
        if network.template.name == 'Public dedicated IPv4':
            public_nets.append(network)
        elif network.template.name == 'Public shared IPv4':
            public_nets.append(network)
        elif network.template.name == 'Private':
            private_net = network
    if not public_nets:
                # ensure there is at least one public network, and default it to dedicated
        nat_net = Network(
                name = slice.name+'-nat',
                    template = NetworkTemplate.objects.get(name='Public shared IPv4'),
                owner = slice
                )
        nat_net.save()
        public_nets.append(nat_net)

    if not private_net:
        private_net = Network(
        name = slice.name+'-private',
        template = NetworkTemplate.objects.get(name='Private'),
        owner = slice
        )
        private_net.save()
    # create slice networks
    public_net_slice = None
    private_net_slice = None
    net_slices = NetworkSlice.objects.filter(slice=slice, network__in=[private_net]+public_nets)
    for net_slice in net_slices:
        if net_slice.network in public_nets:
            public_net_slice = net_slice
        elif net_slice.network == private_net:
            private_net_slice = net_slice
    if not public_net_slice:
        public_net_slice = NetworkSlice(slice=slice, network=public_nets[0])
        public_net_slice.save()
    if not private_net_slice:
        private_net_slice = NetworkSlice(slice=slice, network=private_net)
        private_net_slice.save()