def arrive(name, roster):
    roster[name] = True
    
def check(name, roster):
    return name in roster

classdict = {}
ans = input("a to arrive, c to check, q to quit")
while ans != "q":
    if ans == "a":
        
        student = input("give a student's name")
        arrive(student, classdict)
    elif ans == "c":
        student= input("who do you want to check?")
        if check(student,classdict):
            print(student,"is here")
        else:
            print(student,"is not here")
            
    ans = input("a to arrive, c to check, q to quit")        
print(classdict)