'Fail unless the object is an instance of the specified classes.
Fail the test unless the object ``obj`` is an instance of
any of ``classes``.'

def failUnlessIsInstance(self, obj, classes, msg=None):

    if (not isinstance(obj, classes)):
        if (msg is None):
            msg = ('%(obj)r    is    not    an    instance    of    any    of    %(classes)r' % vars())
        raise self.failureException(msg)
