This question evaluates object-oriented design and implementation skills in Python within the Coding & Algorithms and software engineering domain, focusing on completing concrete subclasses in an existing abstract class hierarchy while preserving public interfaces and type compatibility.
You are given an existing Python codebase that defines multiple classes, including abstract base classes using abc.ABC and @abstractmethod decorators. Without modifying public interfaces or abstract base classes, implement the missing logic in the concrete subclasses so that the system works end-to-end. Constraints: