Python also allows you to create your own exceptions by deriving classes from the standard built-in exceptions.
Here is an example related to RuntimeError. Here, a class is created that is subclassed from RuntimeError. This is useful when you need to display more specific information when an exception is caught.
In the try block, the user-defined exception is raised and caught in the except block. The variable e is used to create an instance of the class Networkerror.
class Networkerror(RuntimeError): def __init__(self, arg): self.args = arg
So once you defined above class, you can raise the exception as follows −
try: raise Networkerror("Bad hostname") except Networkerror,e: print e.args