Question

I want to create a function that can check if the passed arg is an Exception or one of its subclasses. As an example, I would like the the second is_exception function call to return True as well.

def is_exception(obj):
    return type(obj) == Exception

print is_exception(Exception('asdf'))   => True
print is_exception(EOFError('asdf'))    => False

thanks!

Answer 1

You can use issubclass:

>>> issubclass(EOFError,Exception)
True
>>> issubclass(EOFError,EOFerror)
True

The signature is “issubclass(A,B)” which will return True if A is a subclass of B, or “issubclass(A,(B1,B2…))” which will return True if A is a subclass of any of B1,B2 etc.