def METHOD_NAME(self):
    mask = iris.cube.Cube(
        [[0, 1, 0], [0, 0, 1]], long_name="mask", units=1
    )
    broadcast_coord = iris.coords.DimCoord([1, 2], long_name="baz")
    mask.add_dim_coord(broadcast_coord, 0)
    mask.add_dim_coord(self.cube.coord("bar"), 1)
    # Create length-1 dimension to enable broadcasting.
    self.cube.add_aux_coord(broadcast_coord[0])
    cube = iris.util.new_axis(self.cube, "baz")
    returned = mask_cube(cube, mask, in_place=False)
    self.assertCML(cube, checksum=False)
    for subcube in returned.slices_over("baz"):
        # Underlying data should have been broadcast across 'baz' dimension.
        np.testing.assert_array_equal(subcube.data, self.cube.data)
    for subcube in returned.slices_over("foo"):
        # Mask should have been broadcast across 'foo' dimension.
        np.testing.assert_array_equal(subcube.data.mask, mask.data)