fix u style unicode strings in python

[samuelcolvin]

Fix https://github.com/pydantic/pydantic/issues/9496

[codspeed-hq[bot]]

CodSpeed Performance Report

Merging #110 will not alter performance

_{Comparing string-decoding-error (eb0e123) with main (366d16a)}

Summary

✅ 73 untouched benchmarks

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

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