[lmeyerov]

Pandas, dask, etc use also have runtime typed cols (dtypes), which is even stronger in pandas 2 and when used with arrow to go to data representation typing for interop/io. (Half of the performance trick of polars.)

And yeah my ??? with all these is, lacking dependent typing or equivalent for row types, it's hard for mypy and friends to statically track individual columns existing and being specific types. And even if we are willing to be explicit about wrapping each DF with a manual definition, basically an arrow schema, I don't think any of these libraries make that convenient? (And is that natively supported by any?)

In louie.ai, we generate python for users, so we can have it generate the types as well... But we haven't found a satisfactory library for that so far...