compat_level documentation is unclear

[etiennebacher]

Description

#17421 replaced the future parameter by compat_level, but it is not clear from the docs (for example for write_ipc()) what this accepts and what the meaning of each value is.

Before (https://docs.pola.rs/api/python/version/0.20/reference/api/polars.DataFrame.write_ipc.html#polars.DataFrame.write_ipc):

future
Setting this to True will write Polars’ internal data structures that might not be available by other Arrow implementations.

After (https://docs.pola.rs/api/python/dev/reference/api/polars.DataFrame.write_ipc.html)

compat_level
Use a specific compatibility level when exporting Polars’ internal data structures.

The PR linked above added some docs for CompatLevel but those are not displayed on the website (the only matches are for the parameter type): https://docs.pola.rs/api/python/dev/search.html?q=CompatLevel#

Link

No response

[redfave]

I stumbled also across this and haven't found anything in the docs regarding the allowed values and consequences of behaviour. It would be nice to have this documented.