Function gen_pyo3_data_enum 

pub fn gen_pyo3_data_enum(enum_def: &EnumDef, core_import: &str) -> String

Generate a PyO3 data enum as a #[pyclass] struct wrapping the core type.

Data enums (tagged unions like AuthConfig) can’t be flat int enums in PyO3. Instead, generate a frozen struct with inner that accepts a Python dict, serializes it to JSON, and deserializes into the core Rust type via serde.

When any variant field is sanitized (its type could not be resolved — e.g. contains dyn Stream + Send which is not Serialize/Deserialize/Default), the serde- based constructor and trait impls are omitted. The constructor body uses todo!() so the generated code still compiles while making it clear the conversion is not available at runtime.