This question evaluates a candidate's skills in object-oriented design, implementing concrete classes from abstract interfaces, file I/O and streaming data transformations, error handling, and integration with a registry and CLI within a Python codebase.
You are given an existing Python codebase (~200 lines shown) that defines an abstract base class DataProcessor with abstract methods load(self), transform(self, record), and save(self, records); a registry/factory that instantiates processors by name; and a CLI that wires them together. Without editing the abstractions, implement a concrete CsvToJsonProcessor that: (