v$"$Create a use case diagram modeling the patient's visit to a medical center. The patient must first schedule an appointment to visit the medical center. The center's secretary is responsible for managing the appointments. Subsequently, the patient is examined by a doctor. If there is no existing medical record, the doctor creates one for the patient. If a medical record exists, the doctor reads it when the patient visits. After the examination, the doctor updates the patient's medical record. Once the examination is complete, the patient pays the examination cost at the medical center's cashier. Additionally, besides the diagrams, provide descriptive elements: title, brief description, actors, basic flow of events, and alternative flows."