/**
 * As a physician, you need to validate the eligibility for a patient based on membership and introduction to None.
 * You need to check if the username is present in the member roster and the age, as well as years of experience, are valid.
 *
 * @param username The username of the patient.
 * @param age The age of the patient.
 * @param yearsExperience The years of experience as a physician.
 * @return The eligibility status of the patient.
 */
fun membershipIntroductionPhysician(username: String, age: Int, yearsExperience: Int): String {

    // Member roster
    val members = listOf("John", "Alice", "Megan", "Brian", "Sarah")

    // Checking membership
    if (username !in members) {
        return "User not found in the member roster. Ineligibility confirmed."
    }

    // Checking age validity
    if (age <= 0) {
        return "Invalid age provided. Age must be a positive number."
    }

    // Checking years of experience validity
    if (yearsExperience < 0) {
        return "Invalid years of experience provided. Years of experience must be non-negative."
    }

    // All checks passed, patient is eligible
    return "Patient is eligible for further evaluation"
}
/**
 * As a physician, you need to validate the eligibility for a patient based on membership and introduction to None.
 * You need to check if the username is present in the member roster and the age, as well as years of experience, are valid.
 *
 * @param username The username of the patient.
 * @param age The age of the patient.
 * @param yearsExperience The years of experience as a physician.
 * @return The eligibility status of the patient.
 */
fun membershipIntroductionPhysician(username: String, age: Int, yearsExperience: Int): String {
/**
 * As a physician, you need to validate the eligibility for a patient based on membership and introduction to None.
 * You need to check if the username is present in the member roster and the age, as well as years of experience, are valid.
 *
 * @param username The username of the patient.
 * @param age The age of the patient.
 * @param yearsExperience The years of experience as a physician.
 * @return The eligibility status of the patient.
 */
fun membershipIntroductionPhysician(username: String, age: Int, yearsExperience: Int): String {

    // Member roster
    val members = listOf("John", "Alice", "Megan", "Brian", "Sarah")

    // Checking membership
    if (username !in members) {
        return "User not found in the member roster. Ineligibility confirmed."
    }

    // Checking age validity
    if (age <= 0) {
        return "Invalid age provided. Age must be a positive number."
    }

    // Checking years of experience validity
    if (yearsExperience < 0) {
        return "Invalid years of experience provided. Years of experience must be non-negative."
    }

    // All checks passed, patient is eligible
    return "Patient is eligible for further evaluation"
}