How to delete btrfs snapshots made by apt?

I'm almost out of diskspace on my root btrfs partition.

According to `btrfs subvolume show` there are a couple snapshots called @apt-snapshots-release-upgrade... followed by the release name.

I want to delete those so I tried a couple commands like `sudo btrfs subvolume delete @apt-snapshot-release-upgrade-groovy-2021-07-23_18:52:08` and others. However they all failed with the error `ERROR: Could not statfs: No such file or directory`.

Then I found a thread on the internet saying that `apt-btrfs-snapshot` could be used for that. I installed it on impish, however, trying to use that program gave the following error:
`
Traceback (most recent call last):
  File "/usr/bin/apt-btrfs-snapshot", line 94, in <module>
    if args.command == "supported":
AttributeError: 'Namespace' object has no attribute 'command'
`

I'm on impish, is it broken on that release?