Design an object-oriented scheduler for a single autonomous vehicle. The vehicle starts at a known location at time 0. Ride requests arrive in input order, and the vehicle must serve accepted requests in that same order. Each request contains: - `request_id` - `request_time` - `pickup_location` - `dropoff_location` Assume a helper function `travel_time(a, b)` returns the travel time between two locations. Requirements: 1. Add a new ride request. 2. Simulate execution of the schedule and return the final completion time. 3. Support a `skip_to_next_event()` operation so the simulation can jump directly to the next arrival, pickup, or drop-off event instead of advancing one time unit at a time. 4. Support `cancel(request_id)` for any request whose pickup has not started yet. 5. Explain the core classes, state transitions, APIs, and how you would test edge cases. Discuss a clean design first; code is optional.