class MyException(Exception):
    def __init__(self, val, val2):
        self.val = val
        self.val2 = val2
        
    def mymethod(self):
        print 'hello world'
        
    def __str__(self):
        return str(self.val)+", "+str(self.val2)
    
try:
    raise MyException('string associated with MyException', 'second string')
except MyException, obj:
    obj.mymethod()