gh-142495: make defaultdict keep existed value when racing with __missing__
#226025
| Job | Run time |
|---|---|
| 5s | |
| 3s | |
| 8s |
defaultdict keep existed value when racing with __missing__
#226025
| Job | Run time |
|---|---|
| 5s | |
| 3s | |
| 8s |