title: Python split string on delimiter but not on a certain variation of such delimiter
body: <p>I want to split a long string in Python based on the delimiter '--', but not split if the '--' is immediately proceeded by 'fail'. Then put the removed delimiter, '--', back on resulting strings in the split array. Below is an example.</p>
  
  <p>I want:</p>
  
  <pre><code>"--conf example1 --conf curl --fail exception --env example2"
  </code></pre>
  
  <p>After the split, become:</p>
  
  <pre><code>["--conf example1", "--conf curl --fail exception", "--env example2"]
  </code></pre>