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Modular Parcel Locker Hub

Design a system for a smart locker hub used by multiple courier services. The system must manage lockers of various sizes (Small, Medium, Large) and assign them to incoming packages based on dimensions. It should handle the lifecycle of a delivery: from courier drop-off (generating a one-time code) to customer pick-up (validating the code and releasing the locker). Consider how the system handles 'expired' packages that aren't picked up within 48 hours.

Key concepts

state patternstrategy patternconcurrency

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