How to write a function that takes a string and prints the letters in decreasing order of frequency?
<p>I got this far:</p>

<pre><code>def most_frequent(string):
    d = dict()
    for key in string:
        if key not in d:
            d[key] = 1
        else:
            d[key] += 1
    return d

print most_frequent('aabbbc')
</code></pre>

<p>Returning:</p>

<pre><code>{'a': 2, 'c': 1, 'b': 3}
</code></pre>

<p>Now I need to:</p>

<ol>
<li>reverse the pair</li>
<li>sort by number by decreasing order</li>
<li>only print the letters out</li>
</ol>

<p>Should I convert this dictionary to tuples or list?</p>
