public function containerTop($container, $ps_args = null)
    {
        return $this->browser->get(
            $this->uri->expand(
                '/containers/{container}/top{?ps_args}',
                array(
                    'container' => $container,
                    'ps_args' => $ps_args
                )
            )
        )->then(array($this->parser, 'expectJson'));
    }