title: What is the way of adding a word to the line below using regular expression in python?
body: <p>I need a regular expression in python to add {\an8} in the start of every line below the lines contains the two words 'position:50.00%' and 'line:10.00%' at the same time, in a format like this one, thanks.</p>
  
  <pre><code>file_content = re.sub(r'line:10.00%[^\n]*(\n*)([\w\W .,:%])', r'\1{\\an8}\2', file_content) 
  </code></pre>
  
  <p>Like this example:</p>
  
  <pre>
  00:05:31.957 --> 00:05:34.835  position:50.00%,start  align:start size:25.24%  line:10.00%
  {\an8}Not yet.
  </pre>