This is the vanilla python interpreter before and after importing some system libs

test.py

devbox% python
Python 2.7.8 (default, Oct 20 2014, 15:05:19) 
[GCC 4.9.1] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> os
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
NameError: name 'os' is not defined
>>> sys
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
NameError: name 'sys' is not defined
>>> re
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
NameError: name 're' is not defined
>>> import os
>>> import sys
>>> import re
>>> os
<module 'os' from '/usr/lib/python2.7/os.pyc'>
>>> sys
<module 'sys' (built-in)>
>>> re
<module 're' from '/usr/lib/python2.7/re.pyc'>
>>>