What

Design a system for users to register a Python UDF so it can be used during a SQL query. This system should be stateless (for now), i.e. it must be part of the user request (or the Flight ticket) without requiring server-side state (esp. NOT the catalog).

Why

Users shall be able to define Python UDFs themselves, without requiring admin intervention.

How

Either find some clever Flight RPC interaction or some way to define the Python source code in-line within the SQL query.