How to return from python function : <p>This is my first programming practice. I have a python function like this: </p>

<pre><code>sum = 0
def summation(a,b):
    sum = a+b
    return sum
</code></pre>

<p>and when I call function as </p>

<pre><code>summation(3,4)
</code></pre>

<p>It does not return anything. Why?</p>
