How to use sys.exc_info()???

[Roy Smith]

I'm stuped with how sys.exc_info() is supposed to work.  If I do:

open ('xxx')

I get:

Traceback (innermost last):
  File "<stdin>", line 1, in ?
IOError: [Errno 2] No such file or directory: 'xxx'

Which is what I expect.  But when I do:

try:
     open ('xxx')
except:
     foo = sys.exc_info()

What I end up with in foo is

(<class exceptions.IOError at 80a7e20>, <exceptions.IOError instance at 80c82d0>, <traceback object at 80c92c8>)

What I don't understand is how to go from the 3-tuple I get back from
exc_info() to the string "No such file or directory"?