How to use **kwargs to fill in format parameters automatically
<p>I want to automate/simplyfy this:</p>

<pre><code>def test(stream, tag):
    subprocess.call('git submodule checkout {stream}-{tag}'.format(stream=stream, tag=tag))
</code></pre>

<p>i.e. I want to get rid of stream=stream and tag=tag and somehow make use of something like **kwargs. Is this possible?</p>
