`import preliz` fails on matplotlib 3.11 (`module 'matplotlib.style' has no attribute 'core'`)

[anevolbap]

Describe the bug

import preliz fails with matplotlib 3.11.0. The line style.core.USER_LIBRARY_PATHS.append(...) in preliz/__init__.py runs at import time and raises AttributeError. matplotlib 3.11 no longer auto-imports the matplotlib.style.core submodule, so the style.core attribute access fails (the submodule still exists, but import matplotlib.style.core is now required to reach it). This affects 0.24.0, 0.25.0, 0.26.0 (latest), and main.

To Reproduce

pip install "matplotlib==3.11.0" "preliz==0.26.0"
python -c "import preliz"

Stack trace:

File ".../preliz/__init__.py", line 31, in <module>
    style.core.USER_LIBRARY_PATHS.append(_preliz_style_path)
AttributeError: module 'matplotlib.style' has no attribute 'core'

Expected behavior

import preliz works on matplotlib 3.11. A fix mirroring the one arviz-plots used (use the new top-level location, fall back to .core for old matplotlib):

if hasattr(style, "USER_LIBRARY_PATHS"):
    style.USER_LIBRARY_PATHS.append(_preliz_style_path)
else:
    style.core.USER_LIBRARY_PATHS.append(_preliz_style_path)
style.reload_library()

Additional context

matplotlib 3.11.0, preliz 0.26.0, Python 3.12, Linux. Found while trying to drop a matplotlib<3.11 pin in pymc-marketing, where preliz is imported lazily via pymc_extras.prior.Prior.constrain.

I reproduced it with uv in a throwaway environment:

uv run --python 3.12 --with "matplotlib==3.11.0" --with "preliz==0.26.0" python -c "import preliz"

[aloctavodia]

Hi @anevolbap, thanks for taking the time to report and diagnose the issue. Would you like to do a PR?

[anevolbap]

Done, opened #727. It guards style.USER_LIBRARY_PATHS with hasattr and falls back to style.core for matplotlib < 3.11, mirroring the arviz-plots fix. Checked import across matplotlib 3.9, 3.10, and 3.11.