def checkRaises(self, excClass, callableObj, *args, **kwargs):
        """Assert that calling callableObj with *args and **kwargs raises an
        exception of type excClass, and return the exception object so that
        further tests on it can be performed.
        """
        try:
            callableObj(*args, **kwargs)
        except excClass as e:
            return e
        else:
            raise self.failureException(excClass % "Expected exception %s not raised")
dataset/ETHPy150Open aparo/pyes/pyes/tests.py/ESTestCase.checkRaises/swapped operands of `%`