Support for pickling sentinel objects as singletons #2735

Job	Run time
Run tests (3.11)	14s
Run tests (3.10)	18s
Run tests (3.9.12)	20s
Run tests (3.10.4)	22s
Run tests (3.12)	16s
Run tests (3.9)	28s
Run tests (3.11.0)	27s
Run tests (3.13.0)	21s
Run tests (3.14)	16s
Run tests (pypy3.11)	21s
Run tests (pypy3.10)	20s
Run tests (3.12.0)	19s
Run tests (pypy3.9)	21s
Run tests (3.13)	15s
Create an issue if daily tests failed	-1s
	4m 37s

Provide feedback