Here we are passing a variable to given exception. We are defining a custom exception ExampleException which is a subclass of base class Exception and also defining the __init__ method. We use a try-except block to raise the exception and pass the variable to the exception as follows.
class ExampleException(Exception): def __init__(self, foo): self.foo = foo try: raise ExampleException("Bar!") except ExampleException as e: print e.foo