ALL software version info

colorcet 3.0.1 arviz 0.12.1 python 3.10/8 matplotlib 3.6.0/1
afaik introduced with recent colorcet/matplotlib release

Description of expected behavior and the observed behavior

When multiple libraries use mpl.colormaps.register(cmap, name=cmap_name) with the same cmap_name, a ValueError: A colormap named "cet_gray" is already registered. is raised. This happens e.g. for colorcet + arviz, both of which define cet_gray (see here for arviz).

What is the desired behavior -- does colorcet want to assume control of that color name, preventing others from accidentally overriding it (in which case arviz, which intends to duplicate the colorcet color, would be responsible)? Or should simultaneous overriding of the global variable be allowed.

Complete, minimal, self-contained example code that reproduces the issue

import arviz
import colorcet

or

import colorcet
import arviz

This prohibits the use of both simultaneously.

Stack traceback and/or browser JavaScript console output

Traceback (most recent call last):
 File "<string>", line 1, in <module>
 File "/home/yannik/env/env/lib/python3.10/site-packages/arviz/__init__.py", line 320, in <module>
   _mpl_cm("gray", _linear_grey_10_95_c0)
 File "/home/yannik/env/env/lib/python3.10/site-packages/arviz/__init__.py", line 317, in _mpl_cm
   register_cmap("cet_" + name, cmap=cmap)
 File "/home/yannik/env/env/lib/python3.10/site-packages/matplotlib/_api/deprecation.py", line 200, in wrapper
   return func(*args, **kwargs)
 File "/home/yannik/env/env/lib/python3.10/site-packages/matplotlib/cm.py", line 248, in register_cmap
   _colormaps.register(cmap, name=name, force=override_builtin)
 File "/home/yannik/env/env/lib/python3.10/site-packages/matplotlib/cm.py", line 149, in register
   raise ValueError(
ValueError: A colormap named "cet_gray" is already registered.