def METHOD_NAME():
    compartments = ["s1", "s2", "s3"]
    matrix = {
        ("s2", "s1"): "1",
        ("s3", "s2"): "2",
        ("s2", "s2"): "2",
        ("s3", "s3"): "3",
    }
    params = Parameters.from_list([3, 4, 5])
    mat = KMatrix(label="", matrix=matrix)
    mat = fill_item(mat, None, params)
    initial_concentration = [1, 0, 0]
    assert not mat.is_sequential(compartments, initial_concentration)
    matrix = {
        ("s2", "s1"): "1",
        ("s2", "s2"): "2",
    }
    compartments = ["s1", "s2"]
    params = Parameters.from_list([0.55, 0.0404])
    mat = KMatrix(label="", matrix=matrix)
    mat = fill_item(mat, None, params)
    initial_concentration = [1, 0]
    print(mat.reduced(compartments))
    assert mat.is_sequential(compartments, initial_concentration)
    wanted_a_matrix = np.asarray(
        [
            [1, -1.079278],
            [0, 1.079278],
        ]
    )
    print(mat.a_matrix_sequential(compartments))
    assert np.allclose(mat.a_matrix_sequential(compartments), wanted_a_matrix)