f-string expression part cannot include a backslash

[ausgerechnet]

The reason why tests do not run successfully on the spheroscope branch are lines 952f. in database.py:

pattern = fr"/{nm.name}(\[{', ?'.join(nm.valency * [r'[^,\s]+?'])}\])"
repl = fr"/{nm.name}__{nm.valency}__v{nm.version}"

This yields a SyntaxError: f-string expression part cannot include a backslash. Does this maybe work in Python3.12, which is why you didn't catch it?