读取用户输入：如何阅读和打印用户输入？

Question

使用此代码：

person = input('Enter your name: ')
print('Hello', person, '!')

像这样：

Enter your name: david

给我这个错误：

Traceback (most recent call last):
  File "test.py", line 1, in <module>
    person = input('Enter your name: ')
  File "<string>", line 1, in <module>
NameError: name 'david' is not defined