negatives and positives in lists
<p>I'm trying to write a function that allows me to add only the positive numbers in a list and only the negative numbers in a list. I don't know where to start with my coding though. Any help would be great thanks!</p>

<p>example:</p>

<pre><code>negpos([-5,5,6,-8,9])
</code></pre>

<p>should return:</p>

<pre><code>[-13, 20]
</code></pre>
