How to use the meshio.vtu function in meshio

def test(mesh, data_type):
    binary, compression = data_type

    def writer(*args, **kwargs):
        return meshio.vtu.write(*args, binary=binary, compression=compression, **kwargs)

    # ASCII files are only meant for debugging, VTK stores only 11 digits
    # 
    tol = 1.0e-15 if binary else 1.0e-10
    helpers.write_read(writer, meshio.vtu.read, mesh, tol)

def writer(*args, **kwargs):
        return meshio.vtu.write(*args, binary=binary, compression=compression, **kwargs)

"Permas": (meshio.permas.write, meshio.permas.read, ["out.dato"]),
        # # "wkt": ".wkt",
        "TetGen": (meshio.tetgen.write, meshio.tetgen.read, ["out.node", "out.ele"],),
        "VTK (binary)": (
            lambda f, m: meshio.vtk.write(f, m, binary=True),
            meshio.vtk.read,
            ["out.vtk"],
        ),
        "VTK (ASCII)": (
            lambda f, m: meshio.vtk.write(f, m, binary=False),
            meshio.vtk.read,
            ["out.vtk"],
        ),
        "VTU (binary)": (
            lambda f, m: meshio.vtu.write(f, m, binary=True),
            meshio.vtu.read,
            ["out.vtu"],
        ),
        "VTU (ASCII)": (
            lambda f, m: meshio.vtu.write(f, m, binary=False),
            meshio.vtu.read,
            ["out.vtu"],
        ),
        "XDMF (binary)": (
            lambda f, m: meshio.xdmf.write(f, m, data_format="Binary"),
            meshio.xdmf.read,
            ["out.xdmf", "out0.bin", "out1.bin"],
        ),
        "XDMF (HDF, GZIP)": (
            lambda f, m: meshio.xdmf.write(f, m, data_format="HDF", compression="gzip"),
            meshio.xdmf.read,
            ["out.xdmf", "out.h5"],

            lambda f, m: meshio.vtu.write(f, m, binary=True),
            meshio.vtu.read,

if fmt == "ansys":
        ansys.write(args.infile, mesh, binary=False)
    elif fmt == "flac3d":
        flac3d.write(args.infile, mesh, binary=False)
    elif fmt == "gmsh":
        gmsh.write(args.infile, mesh, binary=False)
    elif fmt == "mdpa":
        mdpa.write(args.infile, mesh, binary=False)
    elif fmt == "ply":
        ply.write(args.infile, mesh, binary=False)
    elif fmt == "stl":
        stl.write(args.infile, mesh, binary=False)
    elif fmt == "vtk":
        vtk.write(args.infile, mesh, binary=False)
    elif fmt == "vtu":
        vtu.write(args.infile, mesh, binary=False)
    elif fmt == "xdmf":
        xdmf.write(args.infile, mesh, data_format="XML")
    else:
        print("Don't know how to convert {} to ASCII format.".format(args.infile))
        exit(1)

    size = os.stat(args.infile).st_size
    print("File size after:  {:.2f} MB".format(size / 1024 ** 2))

args.infile, mesh, compression="gzip", compression_opts=9 if args.max else 4
        )
    elif fmt == "mdpa":
        mdpa.write(args.infile, mesh, binary=True)
    elif fmt == "med":
        med.write(
            args.infile, mesh, compression="gzip", compression_opts=9 if args.max else 4
        )
    elif fmt == "ply":
        ply.write(args.infile, mesh, binary=True)
    elif fmt == "stl":
        stl.write(args.infile, mesh, binary=True)
    elif fmt == "vtk":
        vtk.write(args.infile, mesh, binary=True)
    elif fmt == "vtu":
        vtu.write(
            args.infile, mesh, binary=True, compression="lzma" if args.max else "zlib"
        )
    elif fmt == "xdmf":
        xdmf.write(
            args.infile,
            mesh,
            data_format="HDF",
            compression="gzip",
            compression_opts=9 if args.max else 4,
        )
    else:
        print("Don't know how to compress {}.".format(args.infile))
        exit(1)

    size = os.stat(args.infile).st_size
    print("File size after:  {:.2f} MB".format(size / 1024 ** 2))

size = os.stat(args.infile).st_size
    print("File size before: {:.2f} MB".format(size / 1024 ** 2))
    mesh = read(args.infile, file_format=args.input_format)

    # # Some converters (like VTK) require `points` to be contiguous.
    # mesh.points = numpy.ascontiguousarray(mesh.points)

    # write it out
    if fmt == "cgns":
        cgns.write(args.infile, mesh, compression=None)
    elif fmt == "h5m":
        h5m.write(args.infile, mesh, compression=None)
    elif fmt == "med":
        med.write(args.infile, mesh, compression=None)
    elif fmt == "vtu":
        vtu.write(args.infile, mesh, binary=True, compression=None)
    elif fmt == "xdmf":
        xdmf.write(args.infile, mesh, data_format="HDF", compression=None)
    else:
        print("Don't know how to decompress {}.".format(args.infile))
        exit(1)

    size = os.stat(args.infile).st_size
    print("File size after:  {:.2f} MB".format(size / 1024 ** 2))

if fmt == "ansys":
        ansys.write(args.infile, mesh, binary=True)
    elif fmt == "flac3d":
        flac3d.write(args.infile, mesh, binary=True)
    elif fmt == "gmsh":
        gmsh.write(args.infile, mesh, binary=True)
    elif fmt == "mdpa":
        mdpa.write(args.infile, mesh, binary=True)
    elif fmt == "ply":
        ply.write(args.infile, mesh, binary=True)
    elif fmt == "stl":
        stl.write(args.infile, mesh, binary=True)
    elif fmt == "vtk":
        vtk.write(args.infile, mesh, binary=True)
    elif fmt == "vtu":
        vtu.write(args.infile, mesh, binary=True)
    elif fmt == "xdmf":
        xdmf.write(args.infile, mesh, data_format="HDF")
    else:
        print("Don't know how to convert {} to binary format.".format(args.infile))
        exit(1)

    size = os.stat(args.infile).st_size
    print("File size after:  {:.2f} MB".format(size / 1024 ** 2))