* [ Tools ]: Update SPDX License Identifiers
* [pre-commit.ci] auto fixes from pre-commit.com hooks
for more information, see https://pre-commit.ci
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Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Static analysis showed some unused variables and imports, and running
the code in Python 3.9 revealed a few invalid escapes (previous versions
of Python silently "fixed" these, so the code change here will not
affect the results).
