Not Working with s3ql and ubuntu 21.04

I have issue with trio

/usr/lib/python3/dist-packages/trio/_core/_multierror.py:468: RuntimeWarning: You seem to already have a custom sys.excepthook handler installed. I'll skip installing Trio's custom handler, but this means MultiErrors will not show full tracebacks.
warnings.warn(
Using 2 upload threads.
Autodetected xxx file descriptors available for cache entries
Detected Swift features for xxx: copy via COPY, Bulk delete 1000 keys at a time, maximum meta value length is 255 bytes
Using cached metadata.
Setting cache size to 13195 MB
Loaded 0 entries from cache
ERROR: Uncaught top-level exception:
Traceback (most recent call last):
File "/usr/bin/mount.s3ql", line 33, in
sys.exit(load_entry_point('s3ql==3.7.0', 'console_scripts', 'mount.s3ql')())
File "/usr/lib/s3ql/s3ql/mount.py", line 131, in main
trio.run(main_async, options, stdout_log_handler)
File "/usr/lib/python3/dist-packages/trio/_core/_run.py", line 1804, in run
raise runner.main_task_outcome.error
File "/usr/lib/s3ql/s3ql/mount.py", line 207, in main_async
block_cache.init(options.threads)
File "/usr/lib/s3ql/s3ql/block_cache.py", line 222, in init
self.trio_token = trio.lowlevel.current_trio_token()
File "/usr/lib/python3/dist-packages/trio/_deprecate.py", line 125, in getattr
raise AttributeError(name)
AttributeError: lowlevel

The traceback reaches s3ql's s3ql/block_cache.py:222 through its mount.s3ql entry point, where it calls trio.lowlevel.current_trio_token(). Start by checking the relevant Trio API history and the compatibility expectations between Trio and s3ql. Done means establishing the supported API path and confirming that mounting no longer fails at this call.