title: How to add # in front of multiple line of code?
body: <p>I see others do this but have no clue how they did.
  As title, if I want to add # in front of multiple line of code so that these code wont run, like this</p>
  
  <pre><code>print A
  print B
  print C
  </code></pre>
  
  <p>Then I want them become </p>
  
  <pre><code># print A
  # print B
  # print C    
  </code></pre>
  
  <p>What is the fastest way? </p>