how to return first element in multiple tuples as keys in dictionary
<p>For example, if</p>

<pre><code>a = {('a','b','c'):2, ('b','c','d'):3}
</code></pre>

<p>I want to return only <code>'a','b'</code>.</p>

<p>I tried:</p>

<pre><code>for key in a:

    return key[0]
</code></pre>

<p>but it only returned <code>'a'</code>.</p>

<p>Is there a proper way of finding first element without using lambda or counter or stuff like that (this is a basic course in python). So, no other input program.</p>
