Tiled multi-page tiff corrupted?

[giacomomarchioro]

Hello,
thanks for this interesting package.
After installing it using pip install git+https://github.com/pearu/pylibtiff in macOS Catilina 10.15.7 (Python 3.8.3 [Clang 10.0.0 ] :: Anaconda, Inc. on darwin) using this test data:

import skimage
import matplotlib.pyplot as plt
import numpy as np
test = skimage.data.astronaut()
plt.imshow(test)

# we dstack many test images togheter to create our test data
data = skimage.data.astronaut()
for i in range(4):
    data = np.dstack([data,data])

I have tried to generate a tiled multi-page tif

from libtiff import TIFF
imagename = "libtiff_astro.tif"
# to open a tiff file for writing:
tif = TIFF.open("/Users/univr/Documents/iipsrv/images/%s"%imagename, mode='w')
# to write a image to tiff file
tif.write_tiles(data,tile_width=256,tile_height=256,compression=None,write_rgb=None)

However, this results in a corrupted file. Can you please give me some hints on how to solve it?
Thanks a lot.
Giacomo