Error when reading python_version from model metadata

[dbkegley]

Describe the bug

2023/01/30 20:46:55.616070366 Unexpected error while running Python API: 'NoneType' object is not iterable
2023/01/30 20:46:55.629334829 Traceback (most recent call last):
2023/01/30 20:46:55.629366867   File "/opt/rstudio-connect/python/connect_fastapi_runtime.py", line 471, in <module>
2023/01/30 20:46:55.629402780     main(sys.argv)
2023/01/30 20:46:55.629437213   File "/opt/rstudio-connect/python/connect_fastapi_runtime.py", line 410, in main
2023/01/30 20:46:55.629438248     user_app = import_app(entrypoint, app_mode)
2023/01/30 20:46:55.629450763   File "/opt/rstudio-connect/python/connect_common_runtime.py", line 132, in import_app
2023/01/30 20:46:55.629451330     module = import_module(module_name)
2023/01/30 20:46:55.629457614   File "/opt/python/3.9.2/lib/python3.9/importlib/__init__.py", line 127, in import_module
2023/01/30 20:46:55.629458124     return _bootstrap._gcd_import(name[level:], package, level)
2023/01/30 20:46:55.629471240   File "<frozen importlib._bootstrap>", line 1030, in _gcd_import
2023/01/30 20:46:55.629473049   File "<frozen importlib._bootstrap>", line 1007, in _find_and_load
2023/01/30 20:46:55.629494192   File "<frozen importlib._bootstrap>", line 986, in _find_and_load_unlocked
2023/01/30 20:46:55.629549681   File "<frozen importlib._bootstrap>", line 680, in _load_unlocked
2023/01/30 20:46:55.629560240   File "<frozen importlib._bootstrap_external>", line 790, in exec_module
2023/01/30 20:46:55.629560893   File "<frozen importlib._bootstrap>", line 228, in _call_with_frames_removed
2023/01/30 20:46:55.629569775   File "/opt/rstudio-connect/mnt/app/app.py", line 7, in <module>
2023/01/30 20:46:55.629570297     v = VetiverModel.from_pin(b, 'ap311532/cars_mpg', version = '100')
2023/01/30 20:46:55.629582672   File "/opt/rstudio-connect/mnt/app/python/env/lib/python3.9/site-packages/vetiver/vetiver_model.py", line 119, in from_pin
2023/01/30 20:46:55.629598822     return cls(
2023/01/30 20:46:55.629630152   File "/opt/rstudio-connect/mnt/app/python/env/lib/python3.9/site-packages/vetiver/vetiver_model.py", line 94, in __init__
2023/01/30 20:46:55.629634383     self.metadata = translator.create_meta(metadata)
2023/01/30 20:46:55.629657150   File "/opt/rstudio-connect/mnt/app/python/env/lib/python3.9/site-packages/vetiver/handlers/base.py", line 95, in create_meta
2023/01/30 20:46:55.629658320     return VetiverMeta.from_dict(metadata, pip_name)
2023/01/30 20:46:55.629671020   File "/opt/rstudio-connect/mnt/app/python/env/lib/python3.9/site-packages/vetiver/meta.py", line 30, in from_dict
2023/01/30 20:46:55.629671562     python_version = tuple(metadata.get("python_version", sys.version_info))
2023/01/30 20:46:55.629685708 TypeError: 'NoneType' object is not iterable

To Reproduce
Steps to reproduce the behavior:

1. Go to '...'
2. Click on '....'
3. Scroll down to '....'
4. See error

Expected behavior

The model runs without errors

Screenshots
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Desktop (please complete the following information):

• OS: py3.9.2-ubuntu1804
• Browser [e.g. chrome, safari]
• Version ``

Additional context

This came up during a customer support ticket from the Connect team. Still waiting to hear back from the customer on the exact Connect/vetiver versions

[isabelizimm]

Thank you for this report! It looks like there is a bug if None is supplied as Python version, since it is trying to coerce it into a tuple. I'm adding a fix in #149 to add proper handling around this.