title: python regex match string does not start with
body: <p>I want to match any string that <strong>does not</strong> start with 4321
  I came about it with the positive condition: match any string that starts with 4321:</p>
  
  <pre><code>^4321.* 
  </code></pre>
  
  <p><a href="https://regex101.com/r/fC1wX4/9" rel="nofollow">regex here</a></p>
  
  <p>Now I want to reverse that condition, for example:</p>
  
  <ul>
  <li><code>1234555</code> passes</li>
  <li><code>12322222</code> passess</li>
  <li><code>None</code> passess</li>
  <li><code>4321ZZZ</code> does not pass</li>
  <li><code>43211111</code> does not pass</li>
  </ul>
  
  <p>Please help me find the simplest regex as possible that accomplishes this.</p>
  
  <p>I am using a mongo regex but the regex object is build in python so please no python code here (like <code>startswith</code>)</p>