Design an object-oriented model for a parking lot management system. Requirements: - The parking lot has multiple levels; each level has multiple parking spots. - Each spot has a size: small, medium, or large. - Vehicles can be of different types: motorcycle, car, or bus/truck. - A vehicle can only be parked in a spot of a compatible size. A bus or truck may require multiple adjacent large spots. - The system must support: - Vehicle entry: find and reserve an appropriate spot (or group of spots) for an incoming vehicle. - Vehicle exit: free the spot(s) and calculate the parking fee based on time parked. - Query operations: report the number of available spots per size and per level, and whether the lot is full. Assumptions: - Ignore distributed systems concerns; you are designing an in-process object-oriented model, not a networked service. - You may assume time and payment processing are handled by simple helper components. Describe: - The main classes, their responsibilities, and key attributes. - The relationships between classes (inheritance, composition, etc.). - The main methods needed to support the above operations. - Any design patterns or principles (for example, SOLID) you apply.