How to use an Exception’s attributes in Python?

Use the as statement. You can read more about this in Handling Exceptions.

>>> try:
...     print(a)
... except NameError as e:
...     print(dir(e))  # print attributes of e
...
['__cause__', '__class__', '__context__', '__delattr__', '__dict__', '__doc__', '__eq__',
 '__format__', '__ge__', '__getattribute__', '__gt__', '__hash__', '__init__', '__le__',
 '__lt__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__',
 '__setstate__', '__sizeof__', '__str__', '__subclasshook__', '__traceback__', 'args',
 'with_traceback']