The number of operands on the left
hand side must match the number of values.  For instance, if
<code>f</code> is a function returning two values,
</p>

<pre>
x, y = f()
</pre>

<p>
assigns the first value to <code>x</code> and the second to <code>y</code>.
In the second form, the number of operands on the left must equal the number