def METHOD_NAME():
    net = nw.case9()
    pp.runpp(net)
    add_virtual_meas_from_loadflow(net)
    # give it a warm start
    net, ppc, eppci = pp2eppci(net)
    estimation_wls = WLSAlgorithm(1e-3, 3)
    estimation_opt = OptAlgorithm(1e-6, 1000)
    eppci = estimation_wls.estimate(eppci)
    eppci = estimation_opt.estimate(eppci, estimator="wls", verbose=False)
    if not estimation_opt.successful:
        raise AssertionError("Estimation failed due to algorithm failing!")
    net = eppci2pp(net, ppc, eppci)
    net_wls = net.deepcopy()
    estimate(net_wls)
    if not (np.allclose(net_wls.res_bus_est.vm_pu.copy(), net.res_bus_est.vm_pu.copy(),
                        atol=1e-2) and
            np.allclose(net_wls.res_bus_est.va_degree.copy(), net.res_bus_est.va_degree.copy(),
                        atol=1e-2)):
        raise AssertionError("Estimation failed!")