Example from README do not work for prg.evaluate function

[msergg]

Example from README do not work for prg.evaluate function

import celpy
from celpy import CELEvalError

env = celpy.Environment()

# Press the green button in the gutter to run the script.
if __name__ == '__main__':
    all_positive = "data.all(x, x>0)"
    breaks = {'data': [1, 2, 3] }

    ast = env.compile(all_positive)
    prgm = env.program(ast)

    prgm.evaluate(breaks)

   .venv/lib/python3.13/site-packages/celpy/evaluation.py", line 1461, in relation
    }[left_op.data]
      ^^^^^^^^^^^^
AttributeError: 'NoneType' object has no attribute 'data'

python -V
Python 3.13.0

[msergg]

Solution is to use python 3.12 o lower

[slott56]

I added import sys; print(sys.version_info) to the demo code shown above.

Using Python 3.13.0 environment at: issue80
Resolved 8 packages in 790ms
      Built cel-python @ file:///Users/slott/github/local/cel-python
Prepared 5 packages in 258ms
Installed 8 packages in 9ms
 + cel-python==0.2.0 (from file:///Users/slott/github/local/cel-python)
 + lark==0.12.0
 + pendulum==3.1.0
 + python-dateutil==2.9.0.post0
 + pyyaml==6.0.2
 + six==1.17.0
 + types-pyyaml==6.0.12.20250516
 + tzdata==2025.2
(issue80) slott@MacBook-Pro-M4 CELPython % python ~/github/local/cel-python/demo/issue_80.py
sys.version_info(major=3, minor=13, micro=0, releaselevel='final', serial=0)

Using the contents of the current main branch, I cannot reproduce the problem. I suspect this is fixed in main, and the next release should resolve this issue.