Rounding down integers to nearest multiple
<p>Is there a function in Python that allows me to round down to the nearest multiple of an integer? </p>

<pre><code>round_down(19,10)=10
round_down(19,5)=15
round_down(10,10)=10
</code></pre>

<p>I conscientiously looked at SO and found nothing related to rounding <strong><em>down</em></strong> to a nearest base. Please keep this in mind before you post links to related questions or flag as duplicate.</p>
