Consider an information system to manage a group of doctors in a practice. Each doctor is associated with a list of patients that he/she treats. The patients are classified into three categories, according to their age. These categories include child, adult, and senior. The doctors are classified according to their specialization into the following categories: pediatrician, oncologist, endocrinologist, and general practitioner. Each doctor is assigned a dedicated administrative assistant who is responsible for managing various functions such as maintaining appointments, collecting payments etc.

Draw a UML class diagram to model the information system for the doctors office.