'Fail if C{instance} is an instance of the given class or of one of the
given classes.
@param instance: the object to test the type (first argument of the
C{isinstance} call).
@type instance: any.
@param classOrTuple: the class or classes to test against (second
argument of the C{isinstance} call).
@type classOrTuple: class, type, or tuple.'

def assertNotIsInstance(self, instance, classOrTuple):

    if isinstance(instance, classOrTuple):
        self.fail(('%r    is    an    instance    of    %s' % (instance, classOrTuple)))
