def METHOD_NAME(dataroot, sim_datalist, sim_dim, **kwargs):
    """
    Create simulated data using create_test_image_3d.
    Args:
        dataroot: data directory path that hosts the "nii.gz" image files.
        sim_datalist: a list of data to create.
        sim_dim: the image sizes, e.g. a tuple of (64, 64, 64).
    """
    if not os.path.isdir(dataroot):
        os.makedirs(dataroot)
    # Generate a fake dataset
    for d in sim_datalist["testing"] + sim_datalist["training"]:
        im, seg = create_test_image_3d(sim_dim[0], sim_dim[1], sim_dim[2], **kwargs)
        nib_image = nib.Nifti1Image(im, affine=np.eye(4))
        image_fpath = os.path.join(dataroot, d["image"])
        check_parent_dir(image_fpath)
        nib.save(nib_image, image_fpath)
        if "label" in d:
            nib_image = nib.Nifti1Image(seg, affine=np.eye(4))
            label_fpath = os.path.join(dataroot, d["label"])
            check_parent_dir(label_fpath)
            nib.save(nib_image, label_fpath)