Function run_python 

pub fn run_python(columns: &[Column<'_>], body: &str) -> ReferenceResult

Run a Python reference body. The columns are exposed as a pandas df (or, when pandas is unavailable, a dict of NumPy arrays). The body calls emit("key", iterable) to return results. Fails the test with captured stderr when Python exits non-zero (missing python3, missing module, or a raised exception).