Why does it not make a new list each time? : <pre><code>&gt;&gt;&gt; def foo(bar=[]):        
...    bar.append("apple")    
...    return bar

&gt;&gt;&gt; foo()
["apple"]
&gt;&gt;&gt; foo()
["apple", "apple"]
&gt;&gt;&gt; foo()
["apple", "apple", "apple"]
</code></pre>

<p>Why did it add in "apple" instead of making a new list?</p>
