title: How can I remove duplicate words in a string with Python?
body: <p>Following example:</p>
  
  <pre><code>string1 = "calvin klein design dress calvin klein"
  </code></pre>
  
  <p>How can I remove the second two duplicates <code>"calvin"</code> and <code>"klein"</code>?</p>
  
  <p>The result should look like </p>
  
  <pre><code>string2 = "calvin klein design dress"
  </code></pre>
  
  <p>only the second duplicates should be removed and the sequence of the words should not be changed! </p>