'Return a dict mapping facility_user_ids to facility user objs, filtered by the zone id(s), facility_id, or group_id'

def _get_facility_users(self, bundle):

    zone_id = bundle.request.GET.get('zone_id')
    zone_ids = bundle.request.GET.get('zone_ids')
    facility_id = bundle.request.GET.get('facility_id')
    group_id = bundle.request.GET.get('group_id')
    if group_id:
        facility_user_objects = FacilityUser.objects.filter(group__id=group_id)
    elif facility_id:
        facility_user_objects = FacilityUser.objects.filter(facility__id=facility_id)
    elif zone_id:
        facility_user_objects = FacilityUser.objects.by_zone(get_object_or_None(Zone, id=zone_id))
    elif zone_ids:
        zone_ids = zone_ids.split(',')
        facility_user_objects = []
        for zone_id in zone_ids:
            facility_user_objects += FacilityUser.objects.by_zone(get_object_or_None(Zone, id=zone_id))
    else:
        facility_user_objects = FacilityUser.objects.all()
    facility_user_dict = {}
    for user in facility_user_objects:
        facility_user_dict[user.id] = user
    return facility_user_dict
