[Level 2] How to know python module come from.
python> print sys.modules {'copy_reg': <module 'copy_reg' from '/usr/lib/python2.6/copy_reg.pyc'>, 'encodings': <module 'encodings' from '/usr/lib/python2.6/encodings/__init__.pyc'>, 'site': <module 'site' from '/usr/lib/python2.6/site.pyc'>, '__builtin__': <module '__builtin__' (built-in)>, '__main__': <module '__main__' (built-in)>, 'encodings.encodings': None, 'abc': <module 'abc' from '/usr/lib/python2.6/abc.pyc'>, 'posixpath': <module 'posixpath' from '/usr/lib/python2.6/posixpath.pyc'>, 'errno': <module 'errno' (built-in)>, 'encodings.codecs': None, '_abcoll': <module '_abcoll' from '/usr/lib/python2.6/_abcoll.pyc'>, 'types': <module 'types' from '/usr/lib/python2.6/types.pyc'>, '_code...