TypeError: 'Pipeline' object is not iterable

I tried to do the preprocessing of screen2words locally by running `python3 -m pix2struct.preprocessing.convert_screen2words
--screen2words_dir=pix2struct/data/screen2words
--rico_dir=pix2struct/data/rico_images` but got this error.
```
Traceback (most recent call last):
File "/usr/lib/python3.10/runpy.py", line 196, in _run_module_as_main
return _run_code(code, main_globals, None,
File "/usr/lib/python3.10/runpy.py", line 86, in _run_code
exec(code, run_globals)
File "/home/bit2atom/pix2struct/pix2struct/preprocessing/convert_screen2words.py", line 110, in
app.run(main)
File "/home/bit2atom/.local/lib/python3.10/site-packages/absl/app.py", line 308, in run
_run_main(main, args)
File "/home/bit2atom/.local/lib/python3.10/site-packages/absl/app.py", line 254, in _run_main
sys.exit(main(argv))
File "/home/bit2atom/pix2struct/pix2struct/preprocessing/convert_screen2words.py", line 104, in main
pipeline(root)
File "/home/bit2atom/pix2struct/pix2struct/preprocessing/convert_screen2words.py", line 95, in pipeline
_ = ((root, summaries) | "ProcessTrain" >> ProcessSplit("train"))
File "/home/bit2atom/.local/lib/python3.10/site-packages/apache_beam/transforms/ptransform.py", line 1110, in __ror__
return self.transform.__ror__(pvalueish, self.label)
File "/home/bit2atom/.local/lib/python3.10/site-packages/apache_beam/transforms/ptransform.py", line 616, in __ror__
replacements = {
File "/home/bit2atom/.local/lib/python3.10/site-packages/apache_beam/transforms/ptransform.py", line 617, in
id(v): p | 'CreatePInput%s' % ix >> Create(v, reshuffle=False)
File "/home/bit2atom/.local/lib/python3.10/site-packages/apache_beam/transforms/core.py", line 3731, in __init__
self.values = tuple(values)
TypeError: 'Pipeline' object is not iterable
```
Am I doing the data preprocessing locally based on gpu right?