Adding the values of a dictionry to another dictionary
<p>I'd like to add the values of a dictionary to another dictionary.  For example:</p>

<pre><code>adict = {1: {'a': 13, 'b': 19, 'c': 15}, 2: {'a': 7, 'b': 2, 'c': 0}}
</code></pre>

<p>If we add <code>{1: {'a': 3, 'b': 9, 'c': 23}}</code> to adict</p>

<p>Then adict should now be:</p>

<pre><code>{1: {'a': 16, 'b': 28, 'c': 38}, 2: {'a': 7, 'b': 2, 'c': 0}}
</code></pre>

<p>If we add <code>{3: {'a': 4}}</code> then adict should now be:</p>

<pre><code>{1: {'a': 16, 'b': 28, 'c': 38}, 2: {'a': 7, 'b': 2, 'c': 0}, 3: {'a': 4}}
</code></pre>

<p>and if we add <code>{2: {'a': 1, 'b': 8, 'c': 27, 'd': 11}}</code></p>

<p>Then adict should now be:</p>

<pre><code>{1: {'a': 16, 'b': 28, 'c': 38}, 2: {'a': 8, 'b': 10, 'c': 27, 'd': 11}, 3: {'a': 4}}
</code></pre>

<p>What's the best way to do this?</p>
