How to use the @angular/router.provideRoutes function in @angular/router

RouterTestingModule.withRoutes = function (routes) {
        return { ngModule: RouterTestingModule, providers: [provideRoutes(routes)] };
    };
    return RouterTestingModule;

static withRoutes(routes, config) {
        return {
            ngModule: RouterTestingModule,
            providers: [
                provideRoutes(routes),
                { provide: ROUTER_CONFIGURATION, useValue: config ? config : {} },
            ]
        };
    }
}

RouterTestingModule.withRoutes = function (routes, config) {
        return {
            ngModule: RouterTestingModule_1,
            providers: [
                provideRoutes(routes),
                { provide: ROUTER_CONFIGURATION, useValue: config ? config : {} },
            ]
        };
    };
    var RouterTestingModule_1;

RouterTestingModule.withRoutes = function (routes) {
        return { ngModule: RouterTestingModule, providers: [provideRoutes(routes)] };
    };
    RouterTestingModule.decorators = [

RouterTestingModule.withRoutes = function (routes, config) {
        return {
            ngModule: RouterTestingModule_1,
            providers: [
                provideRoutes(routes),
                { provide: ROUTER_CONFIGURATION, useValue: config ? config : {} },
            ]
        };
    };
    var RouterTestingModule_1;

static withRoutes(routes) {
        return { ngModule: RouterTestingModule, providers: [provideRoutes(routes)] };
    }
}

RouterTestingModule.withRoutes = function (routes) {
        return { ngModule: RouterTestingModule, providers: [provideRoutes(routes)] };
    };
    return RouterTestingModule;

static withRoutes(routes, config) {
        return {
            ngModule: RouterTestingModule,
            providers: [
                provideRoutes(routes),
                { provide: ROUTER_CONFIGURATION, useValue: config ? config : {} },
            ]
        };
    }
}

RouterTestingModule.withRoutes = function (routes) {
        return { ngModule: RouterTestingModule, providers: [provideRoutes(routes)] };
    };
    RouterTestingModule.decorators = [

beforeEach(() => {
        TestBed.configureTestingModule({
            declarations: [
                TestRouterComponent,
                AppComponent
            ],
            imports: [ RouterTestingModule, RouterModule, CoreModule ],
            providers: [ provideRoutes(config) ]
        });
    });