fix: deeprecation warning about _UnionGenericAlias'

[FomalhautWeisszwerg]

About This Pull Request

Type

fix

Summary

When using google-genai on Python 3.14, following warning is raised

DeprecationWarning: '_UnionGenericAlias' is deprecated and slated for removal in Python 3.17

This PR fixes the warning reported #1640 and improves future compatibility.

Detail

Currently, google-genai uses the CPython's private object typing._UnionGenericAlias. However typing._UnionGenericAlias is deprecated and planned to remove until Python 3.17. And google-genai required Python >= 3.10 so the fallback branch for Python <= 3.10 no longer needed.

The changes are

• drop typing._UnionGenericAlias importing
• remove fallback branch for Python <= 3.10

I hope that I could be of some help, even if only a little.
Thanks for reviewing.

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[Venkaiahbabuneelam]

Hi @FomalhautWeisszwerg, Thanks for reaching out us!

I can see that few checks were failed for the above PR, could you please check once.

Thanks

[FomalhautWeisszwerg]

@Venkaiahbabuneelam Thanks for reviewing.

To fix it, I've added # type: ignore because the definition _UNION_TYPES = (typing.Union, builtin_types.UnionType) is just for supporting both Union[t1, t2] and t1 | t2.