source:
{}['x']

result:
python2.4 ./test.py
Traceback (most recent call last):
  File "./test.py", line 3, in ?
    {}['x']
KeyError: 'x'


---------

source:
try:
    {}['x']
except Exception, e:
    print e.args[0]

result:
python2.4 ./test.py