Clarify getppid documentation: explain how None can occur
#4439
| Job | Run time |
|---|---|
| 54s | |
| 5m 44s | |
| 5m 52s | |
| 5s | |
| 6m 1s | |
| 58s | |
| 42s | |
| 1m 2s | |
| 46s | |
| 36s | |
| 1m 3s | |
| 52s | |
| 59s | |
| 53s | |
| 24s | |
| 1m 4s | |
| 57s | |
| 1m 0s | |
| 1m 5s | |
| 1m 5s | |
| 1m 10s | |
| 4m 51s | |
| 56s | |
| 1m 3s | |
| 35s | |
| 59s | |
| 1m 6s | |
| 1m 5s | |
| 1m 8s | |
| 59s | |
| 56s | |
| 2m 24s | |
| 2m 37s | |
| 2m 41s | |
| 2m 38s | |
| 2m 37s | |
| 2m 45s | |
| 2m 43s | |
| 31s | |
| 46s | |
| 43s | |
| 1m 5s | |
| 41s | |
| 1h 9m 1s |