对于函数ask,以下调用错误的是哪一项?( )。1. def ask(prompt = ""Do you like Python? "", hint = ""yes or no""):
2. while True:
3. answer = raw_input(prompt)
4. if answer.lower() in ('y', 'yes'):
5. print ""Thank you""
6. return True
7. if answer.lower() in ('n', 'no'):
8. print ""Why not ""
9. return False
10. else:
11. print hint