def METHOD_NAME(fermi_datasets):
    estimator = FluxEstimator(0, selection_optional=None, reoptimize=True)
    datasets = fermi_datasets.slice_by_energy(energy_min="1 GeV", energy_max="100 GeV")
    datasets.models = fermi_datasets.models
    result = estimator.run(datasets)
    assert_allclose(result["norm"], 0.989989, atol=1e-3)
    assert_allclose(result["ts"], 18729.368105, rtol=1e-3)
    assert_allclose(result["norm_err"], 0.01998, atol=1e-3)