checks using sets in blocks are not represented correctly in string dumps #58

Hello All,

Thanks for all you hard work on biscuits , i'm a big fan !

i am using biscuit-python 0.4.0 and i think i have found a bug in the string representation of the a check containing a set .

this looks like its just in the python side because the underlying behaviour is correct.

This test case creates an authority and adds some blocks to it which contain checks against a set

In the string representation of the blocks the names of the set variables seem to be repeated from the first one.
In the string representation of the authoriser the names of the set variables in the blocks seem to be correct and the behavior is correct.

I wrote this using pycharm on windows 11 with python 3.12

sets_testcase.py

Cheers
Amias