checking if an object is an Exception class

Question

I've got some code which does:

try:
    result = func()
except StandardError as e:
    result = e

How can I check whether result contains an Exception?

Using isinstance(result, Exception) doesn't work as exceptions are a class, not an instance, e.g. type(ValueError) gives <type 'type'>.

--- Edit ---

Well that was stupid; while the above code was a correct distillation of how I was using func(), what my test func() was doing was return ValueError, not raise ValueError. With the former returning the class and the latter returning an instance. So the problem wasn't as described.

Answer 1

Though I am convinced that this is an XY Problem that requires rethinking the logic of your design, here is an answer to your immediate question: isinstance works fine:

>>> try:
...     int('a')
... except ValueError as e:
...     result = e
...
>>> type(result)
<class 'ValueError'>
>>> isinstance(result, Exception)
True

Your problem is that you were testing ValueError (the class), not e (an instance of a ValueError). Perhaps the following example with a bool (which subclasses an int) will make this clearer:

>>> isinstance(bool, int)
False
>>> isinstance(True, int)
True