Dear Daniel, Michael,
Thanks for the reply and sorry for posting many times.
Both 046_checkpoint_logical and 047_checkpoint_physical has below comments:
```
# Run another checkpoint, this time in the background, and make it wait
# on the injection point) so that the checkpoint stops right before
# removing old WAL segments.
```
Is "injection point)" a typo? I feel it is enough to remove ")".
Feel free to include if you agree this point as well.
Best regards,
Hayato Kuroda
FUJITSU LIMITED