ImportError with arviz >= 1.0: module 'arviz' has no attribute 'InferenceData'

[twiecki]

CausalPy fails to import with arviz >= 1.0.

Error:

import causalpy as cp
# → AttributeError: module 'arviz' has no attribute 'InferenceData'

The error comes from pymc's util.py (line 244) which uses arviz.InferenceData as a type annotation. In arviz 1.0, InferenceData was moved to arviz-base and removed from the top-level arviz namespace.

Suggested fix: Pin arviz<1.0 in CausalPy's dependencies until pymc supports arviz 1.0.

Environment: Python 3.13, latest CausalPy from PyPI, arviz 1.0