Unicode question

[Ben Edwards (lists)]

I am using python 2.4 on Ubuntu dapper, I am working through Dive into
Python.

There are a couple of inconsictencies.

Firstly sys.setdefaultencoding('iso−8859−1') does not work, I have to do
sys.setdefaultencoding = 'iso−8859−1'

secondly the following does not give a 'UnicodeError: ASCII encoding
error:', and I would expect ti to.  In fact it prints out the n with ~
above it fine:

sys.setdefaultencoding = 'ascii'
s = u'La Pe\xf1a'
print s

Any insight?
Ben