def METHOD_NAME(filename, output_folder):
    img_itk = sitk.ReadImage(filename)
    dim = img_itk.GetDimension()
    file_base = filename.split("/")[-1]
    if dim == 3:
        shutil.copy(filename,
                    join_paths(output_folder, file_base[:-7] + "_0000.nii.gz"))
        return
    elif dim != 4:
        raise RuntimeError(
            "Unexpected dimensionality: {} of file {}, cannot split".format(
                dim, filename))
    else:
        split_4d_to_3d_and_save(img_itk, output_folder, file_base)