def setname(cls):
    '''this is the proposed generator to call SetName on the object'''
    try:
        cls.SetName(cls.__name__)
    finally:
        yield cls

class Trial:
    '''class to demonstrate with'''
    def SetName(self, name):
        print 1, 1

@setname
class Test(Trial):
    '''i want SetName to be called by using setname as a decorator'''
    def __init__(self):

        print 'Yay! or Invalid.'

if __name__ == '__main__':
    test = Test()