check username in confirmed username

gistfile1.txt

unconfirmed_users = ["peter", "tom", "mark", "brian", "agus", "tom", "travis"]
confirmed_users = []

while unconfirmed_users:
    current_user = unconfirmed_users.pop()
    if current_user not in confirmed_users:
        print("Verifying user: " + current_user.title())
        confirmed_users.append(current_user)
print("\nThe following users have been confirmed:")
for confirmed_user in confirmed_users:
    print(confirmed_user.title())