Plot Atlas AAL giving an error for .nii 3D image

I wanted to plot a few of the regions from AAL atlas. I ran the following code but it gives an error that the map is not 4D. Is there any way to fix this?

dataset = datasets.fetch_atlas_aal()
display = plotting.plot_stat_map(image.index_img(maps, 6),colorbar=False)

Error :
raise DimensionError(len(niimg.shape), ensure_ndim)
nilearn._utils.exceptions.DimensionError: Input data has incompatible dimensionality: Expected dimension is 4D and you provided a 3D image. See

the aal map contains integer identifiers of the regions, not one map per region.
roi = image.new_image_like(aal.maps, aal.maps.get_data() == <some integer>) to isolate one region