Fix regex escape characters in documentation

[DrStone1971]

Fix for vllm

error:

vllm
/home/tore/.venvs/comfy/lib/python3.12/site-packages/torchao/quantization/quant_api.py:1501: SyntaxWarning: invalid escape sequence '.'
"""Configuration class for applying different quantization configs to modules or parameters based on their fully qualified names (FQNs).

[pytorch-bot]

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[DrStone1971]

This PR fixes Python SyntaxWarning caused by invalid escape sequences in docstring regex examples.
The regex examples are documentation-only and now escape backslashes correctly for Python string literals.

[andrewor14]

@claude review

[claude]

Claude finished @andrewor14's task in 52s —— View job

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Code Review: Fix regex escape characters in documentation

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LGTM ✅

This is a correct and straightforward fix. The docstring at torchao/quantization/quant_api.py:1501 is a regular (non-raw) string, so \. is an invalid escape sequence that triggers a SyntaxWarning in Python 3.12+. The fix correctly doubles the backslashes (\\.) so that the rendered docstring still shows the intended regex pattern \..

Details:

• Lines 1515, 1517: re:language\.layers\..+\.q_proj → re:language\\.layers\\..+\\.q_proj — correct
• No other instances of this issue found in the file
• The alternative approach would be to make this a raw docstring (r"""..."""), but doubling the backslashes is equally valid and a smaller change

One minor note: On line 1515, the trailing .weight still uses an unescaped . (i.e., q_proj.weight rather than q_proj\.weight). This is technically a regex wildcard, not a literal dot. However, since this is just an illustrative example in documentation and not executed code, it's fine to leave as-is — the PR author's fix addresses the actual SyntaxWarning correctly.

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[jerryzh168]

I feel the fix should be add a r in L1501 before """?

[jerryzh168]

see #3825

can you help test this