mypy

gh-152951 - Fix double DECREF when `newblock` fails during deque.exte… #22297

Job	Run time
Run mypy on Lib/_pyrepl	32s
Run mypy on Lib/test/libregrtest	31s
Run mypy on Tools/cases_generator	32s
Run mypy on Tools/clinic	31s
Run mypy on Lib/tomllib	29s
Run mypy on Tools/peg_generator	29s
Run mypy on Tools/check-c-api-docs	27s
Run mypy on Tools/build	29s
Run mypy on Tools/jit	31s
	4m 31s

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