name = 'sum/2'
slug = 'find the sum of all elements in list'

description = '''\
<p><code>sum(L, Sum)</code>: <code>Sum</code> is the sum of all elements in the list <code>L</code>.</p>
<pre>
?- sum([1,2,3], Sum).
  Sum = 6.
</pre>'''

hint = {}