where can I find good reference document on python exception

It doesn't seem easy to find good reference document that details all python exceptions.

For example, whenever I got IOError exception, it has a different message format but I could not find any good reference:

IOError: ('http protocol 开发者_JAVA技巧error', 0, 'got a bad status line', None)

or

IOError: [Errno socket error] [Errno 110] Connection timed out

Built-in Exceptions are documented, here's IOException. Check errno documentation for symbol definition, errno.errorcode is a dict containing a mapping between error code/symbols.

import errno
errno.errorcode[numeric_code]

I guess that you are looking for errno:

try:
    open('file_dont_exist')
except IOError as ex:
    if ex.errno == errno.ENOENT:
        print "no such file or directory"