Dataframe issues

[patrick-nicodemus]

I have started trying to use owl for a project to identify good avenues for improvement. Two issues I came across when I tried using dataframes:

• Option types are a must, it's very common to have partial data in the real world. Polars has data series for float and float option, int and int option, etc.
• It is not clear what the point of the Any_Series series item or Any element type is. It is not a wrapper around any data so it appears useless? Is there some utility to this?

(As per the recent discussion on discuss.ocaml.org, I understand that the project lead does not have time for maintenance work, and therefore this issue should not be interpreted as a request for the project lead to resolve this, but rather as public documentation of an issue for someone to fix when they have time, possibly myself.)