>>> help()
help> modules os
Here is a list of matching modules.  Enter any module name to get more help.

posix - This module provides access to operating system
...
stringprep - Library that exposes various tables found in the StringPrep
RFC 3454.
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
...
File "/home/michael/python3/3.0b1/lib/python3.0/codecs.py", line 300, in
decode
(result, consumed) = self._buffer_decode(data, self.errors, final)
UnicodeDecodeError: 'utf8' codec can't decode bytes in position 8-11:
invalid data