[问题求助-程序运行错误]“unexpected EOF while parsing”，几乎按照教材上的代码写的，为毛还会出现这种错误/(ㄒoㄒ)/~~

catNames = []

while True:
print('please enter the name of your cat:')
name = str(input())
if name == str():
break
catNames = catNames + [name]

print('the cas name are:' + catNames )

报错：
Traceback (most recent call last):
File "/Users/mrdongzhijie/Python/statisc-c4.py", line 5, in <module>
name = input()
File "<string>", line 0

^
SyntaxError: unexpected EOF while parsing

附加问题：
为毛代码已经将输入转换为 str，结果在交互环境输入字符时还要加‘’，否则就要报错？