How to use the pygmsh.get_gmsh_major_version function in pygmsh

@pytest.mark.skipif(pygmsh.get_gmsh_major_version() < 3, reason="requires Gmsh >= 3")
def test():
    geom = pygmsh.opencascade.Geometry()

    geom.add_ellipsoid([1.0, 1.0, 1.0], [1.0, 2.0, 3.0], char_length=0.1)

    ref = 8.0 * pi
    mesh = pygmsh.generate_mesh(geom)
    assert abs(compute_volume(mesh) - ref) < 1.0e-2 * ref
    return mesh

@pytest.mark.skipif(pygmsh.get_gmsh_major_version() < 3, reason="requires Gmsh >= 3")
def test():
    geom = pygmsh.opencascade.Geometry()

    geom.add_cone(
        [0.0, 0.0, 0.0], [0.0, 0.0, 1.0], 1.0, 0.3, 1.25 * pi, char_length=0.1
    )

    ref = 0.90779252263
    mesh = pygmsh.generate_mesh(geom)
    assert abs(compute_volume(mesh) - ref) < 1.0e-2 * ref
    return mesh

@pytest.mark.skipif(pygmsh.get_gmsh_major_version() < 3, reason="requires Gmsh >= 3")
def test():
    geom = pygmsh.opencascade.Geometry()

    geom.add_box([0.0, 0.0, 0.0], [1, 2, 3], char_length=0.1)

    ref = 6
    mesh = pygmsh.generate_mesh(geom)
    assert abs(compute_volume(mesh) - ref) < 1.0e-2 * ref
    return mesh

@pytest.mark.skipif(pygmsh.get_gmsh_major_version() < 3, reason="requires Gmsh >= 3")
def test():
    geom = pygmsh.opencascade.Geometry(
        characteristic_length_min=2.0, characteristic_length_max=2.0
    )

    rect1 = geom.add_rectangle([10.0, 0.0, 0.0], 20.0, 40.0, corner_radius=5.0)
    rect2 = geom.add_rectangle([0.0, 10.0, 0.0], 40.0, 20.0, corner_radius=5.0)
    disk1 = geom.add_disk([14.5, 35.0, 0.0], 1.85)
    disk2 = geom.add_disk([25.5, 5.0, 0.0], 1.85)

    rect3 = geom.add_rectangle([10.0, 30.0, 0.0], 10.0, 1.0)
    rect4 = geom.add_rectangle([20.0, 9.0, 0.0], 10.0, 1.0)

    r1 = geom.add_rectangle([9.0, 0.0, 0.0], 21.0, 20.5, corner_radius=8.0)
    r2 = geom.add_rectangle([10.0, 00.0, 0.0], 20.0, 19.5, corner_radius=7.0)
    diff1 = geom.boolean_difference([r1], [r2])

@pytest.mark.skipif(pygmsh.get_gmsh_major_version() < 3, reason="requires Gmsh >= 3")
def test():
    geom = pygmsh.opencascade.Geometry()

    geom.add_wedge([0.0, 0.0, 0.0], [1.0, 1.0, 1.0], top_extent=0.4, char_length=0.1)

    ref = 0.7
    mesh = pygmsh.generate_mesh(geom)
    assert abs(compute_volume(mesh) - ref) < 1.0e-2 * ref
    return mesh

@pytest.mark.skipif(pygmsh.get_gmsh_major_version() < 3, reason="requires Gmsh >= 3")
def test():
    geom = pygmsh.opencascade.Geometry()

    geom.add_ball(
        [0.0, 0.0, 0.0], 1.0, x0=-0.9, x1=+0.9, alpha=0.5 * pi, char_length=0.1
    )

    ref = 0.976088698545
    mesh = pygmsh.generate_mesh(geom)
    assert abs(compute_volume(mesh) - ref) < 1.0e-2 * ref
    return mesh

@pytest.mark.skipif(pygmsh.get_gmsh_major_version() < 3, reason="requires Gmsh >= 3")
def test():
    geom = pygmsh.opencascade.Geometry()

    geom.add_torus([0.0, 0.0, 0.0], 1.0, 0.3, 1.25 * pi, char_length=0.1)

    ref = 1.09994740709
    mesh = pygmsh.generate_mesh(geom)
    assert abs(compute_volume(mesh) - ref) < 1.0e-2 * ref
    return mesh

lcar = 0.1
    p1 = geom.add_point([0.0, 0.0, 0.0], lcar)
    p2 = geom.add_point([1.0, 0.0, 0.0], lcar)
    p3 = geom.add_point([1.0, 0.5, 0.0], lcar)
    p4 = geom.add_point([1.0, 1.0, 0.0], lcar)
    s1 = geom.add_bspline([p1, p2, p3, p4])

    p2 = geom.add_point([0.0, 1.0, 0.0], lcar)
    p3 = geom.add_point([0.5, 1.0, 0.0], lcar)
    s2 = geom.add_bspline([p4, p3, p2, p1])

    ll = geom.add_line_loop([s1, s2])
    geom.add_plane_surface(ll)

    ref = 0.9156598733673261 if pygmsh.get_gmsh_major_version() < 4 else 0.75
    mesh = pygmsh.generate_mesh(geom)
    assert abs(compute_volume(mesh) - ref) < 1.0e-2 * ref
    return mesh

def generate():
    if pg.get_gmsh_major_version() == 3:
        # factories are supported only in gmsh 3
        geom = pg.Geometry(factory_type='OpenCASCADE')
    else:
        geom = pg.Geometry()

    geom.add_box(0, 1, 0, 1, 0, 1, 1.0)
    return geom, 1.0

@pytest.mark.skipif(pygmsh.get_gmsh_major_version() < 3, reason="requires Gmsh >= 3")
def test_union():
    geom = pygmsh.opencascade.Geometry(
        characteristic_length_min=0.1, characteristic_length_max=0.1
    )

    rectangle = geom.add_rectangle([-1.0, -1.0, 0.0], 2.0, 2.0)
    disk_w = geom.add_disk([-1.0, 0.0, 0.0], 0.5)
    disk_e = geom.add_disk([+1.0, 0.0, 0.0], 0.5)
    geom.boolean_union([rectangle, disk_w, disk_e])

    ref = 4.780361
    mesh = pygmsh.generate_mesh(geom)
    assert abs(compute_volume(mesh) - ref) < 1.0e-2 * ref
    return mesh