title: How do I check if a user left the 'input' or 'raw_input' prompt empty?
body: <p>How do I check if input has been entered?</p>
  <p>For example (python2)</p>
  <pre><code>x = str(raw_input('Message&gt;&gt; '))
  </code></pre>
  <p>or
  (python3)</p>
  <pre><code>y = input('Number&gt;&gt; ')
  </code></pre>