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factory

Shape-based preprocessor factory shared by every consuming step.

A step declares an ordered list of (shape_detector, pipeline) candidates and gets a uniform preprocess(df, *, datasource) from build_preprocessor. Centralising the shape-matching loop keeps every step's preprocessing.py to the same shape — a _CANDIDATES list and a preprocess — with no duplicated loop or divergent no-match handling.

Module​

Functions​

build_preprocessor​

def build_preprocessor(    candidates: Sequence[ShapeCandidate], *, step_name: str,) ‑> collections.abc.Callable[..., pandas.core.frame.DataFrame]:

Build a step's preprocess from its ordered shape candidates.

Arguments

  • candidates: Ordered (shape_detector, pipeline) pairs. The first detector that matches the frame wins; its pipeline is applied.
  • step_name: The consuming step's name, used in the no-match warning.

Returns preprocess(df, *, datasource): applies the first matching candidate's pipeline, or returns df unchanged when it is empty or no candidate matches (passthrough + warn).