When visitors will travel some place, they will first find a travel agency, pay the fee, then the travel agency assign the visitor to the experienced guide, then the guide take visitors to the places they want to view, the
guide will follow the itinerary, take visitors tour every place, if itinerary has accommodation, then the guide assign visitors room to sleep.
This package of code simulate the process, define tourist, guide, travel agency, hotel, tour objects, make them work together, guide takes tourist to travel the places according the itinerary.
Guide is the person to accompany with tourists and tour them.
Tour is the travel itinerary, it has travel city, the date time to travel, the place detail.
Travel agency can add guide person, add tourist, organize guide, organize the hotel and pay hotel the right fee.