bpo-33747: Avoid mutating the global sys.modules dict in unittest.mock tests (GH-8520)
bpo-33747: Avoid mutating the global sys.modules dict in unittest.mock tests (GH-8520)

Backports: 3cf74384b53b998fa846dc2590cedf9ad2a0d5fd
Signed-off-by: Chris Withers <711c73f64afdce07b7e38039a96d2224209e9a6c@withers.org>

testing-cabal/mock