我所做的是以下内容:
Python 2.7.2 (default, Jun 12 2011, 15:08:59) [MSC v.1500 32 bit (Intel)] on win32
Type "copyright", "credits" or "license()" for more information.
>>> import sys
>>> print sys.modules['idlelib.sys']
None
>>> 'idlelib.sys' in sys.modules
True
为什么会有这个空模块?