exceptions with spaces don't work??

[Paul Probert]

As a python newbie, I came across a problem:
If I raise an exception with a string, as in:
    raise 'somestring'
then my statement
    except 'somestring':
will catch it unless there are spaces. For instance
suppose I have a file ext.py:

def re():
   raise 'x y'
   return 3
	
try:
   print 'calling re'
   x=re()
except 'x y':
   print 'got it'

now execute it:
 >>> execfile('ext.py')
calling re
Traceback (most recent call last):
   File "<stdin>", line 1, in ?
   File "ext.py", line 7, in ?
     x=re()
   File "ext.py", line 2, in re
     raise 'x y'
x y

now replace the spaces with _:

def re():
   raise 'x_y'
   return 3
	
try:
   print 'calling re'
   x=re()
except 'x_y':
   print 'got it'

 >>> execfile('ext.py')
calling re
got it

Is this a bug??

-- 
Paul Probert
The University of Wisconsin-Madison