title: Combining Tuples into a List
body: <p>I have a list of tuples:</p>
  <pre class="lang-py prettyprint-override"><code>[(1,2), (5,10), (2,5)]
  </code></pre>
  <p>And I would like to get a list of unique numbers</p>
  <pre><code>[1,2,5,10]
  </code></pre>
  <p>May I know how can I achieve that?</p>