使用httplib2模块时遇到的奇怪问题

Traceback (most recent call last):
File "C:\Users\WeakDancer\Desktop\mail.py", line 7, in <module>
import httplib2
File "C:\Users\WeakDancer\Desktop\httplib2.py", line 5, in <module>
http = httplib2.Http()
AttributeError: 'module' object has no attribute 'Http'
>>>

>　http = httplib2.Http()
这句创建一个实例，在shell中正常，文件直接执行就报错，很奇怪。