How to use the cartoview.connections.models.Server.objects.get function in cartoview

def harvest_resources(request, server_id):
    try:
        server = Server.objects.get(id=server_id)
    except ObjectDoesNotExist:
        messages.error(request, "Server Not Found")
    user = request.user
    harvest_task.delay(server.id, user_id=user.id or None)
    index_url = "%s_%s_modeladmin_index" % (Server._meta.app_label, Server._meta.model_name)
    messages.success(request, "Server Resources Will Be Collected")
    return redirect(index_url)

def delete_invalid_resources(self, request, pk=None):
        try:
            server = Server.objects.get(pk=pk)
        except ObjectDoesNotExist as e:
            return Response({"details": str(e)},
                            status=status.HTTP_500_INTERNAL_SERVER_ERROR)
        delete_invalid_resources.delay(server.id)
        return Response({"message":
                         _("Invalid Server Resources Will Be Deleted")},
                        status=status.HTTP_202_ACCEPTED)

def __init__(self, base_url, server_id, user_id=None):
        self.url = base_url
        self.server = Server.objects.get(id=server_id)
        self.user_id = user_id
        self.user = None
        if user_id:
            USER = get_user_model()
            self.user = USER.objects.get(id=user_id)

def serve(self, request, pk, *args, **kwargs):
        server = Server.objects.get(pk=pk)
        user = request.user
        user_id = None if not user else user.id
        conn = server.get_user_connections(user_id).first()
        allowed = False
        params = {}
        if conn:
            conn = conn.credentials
            if request.method in permissions.SAFE_METHODS:
                allowed = user.has_perm('use_for_read', conn)
            else:
                allowed = user.has_perm('use_for_write', conn)
            if isinstance(conn, TokenAuthConnection):
                params.update({'access_token': conn.token})
        if allowed:
            logger.info("ALLOWED To USE SESSION")
            session = server.handler(user_id=user_id).session

def update_server_resources(self, request, pk=None):
        try:
            server = Server.objects.get(pk=pk)
        except ObjectDoesNotExist as e:
            return Response({"details": str(e)},
                            status=status.HTTP_500_INTERNAL_SERVER_ERROR)
        update_server_resources.delay(server.id, user_id=request.user.id or None)
        return Response({"message":
                         _("Server Resources Will Be Updated")},
                        status=status.HTTP_202_ACCEPTED)