def remove(self, elem):
        """Remove a requirement.

        :param elem: a string or :class:`Requirement` instance.
        """
        if isinstance(elem, text_type):
            for requirement in self:
                if requirement.package == elem:
                    return super(Requirements, self).remove(requirement)
        return super(Requirements, self).remove(elem)
def test_cache_middleware(self):
        req = Request.blank('/something', environ={'REQUEST_METHOD': 'GET'})
        resp = self.app(req.environ, start_response)
        self.assertTrue('swift.cache' in resp)
        self.assertTrue(isinstance(resp['swift.cache'], MemcacheRing))